Violence as an integral part of daily life: pain and death are constant themes in the work of the Mexican artist Teresa Margolles. The Museion exhibition tackles the murders and disappearances in the city of Jaurez in Mexico: a central element of the presentation is a wall with visible bullet holes left by executioners.

The show also features a filmed action created by the artist in Bolzano, inspired by the thought that all places have a story of suffering etched into their past.

At first glance, her works often seem to be minimalist in their form. Viewers only discover that they are deeply emotional and dramatic when they become aware of the rigorous realism in the choice of material.

Muro Baleado (Culiacán), 2009

The two walls shown in the exhibition were removed from Mexican cities and replaced with new walls. The man-high concrete-block walls are witnesses of daily violence: they display bullet holes resulting from shoot-outs that have had a lasting impact on cities such as Ciudad Juárez, where the drug war is raging with particular vehemence.

Muro Ciudad Juárez, 2010

With the title Frontera (frontier), Teresa Margolles alludes to the limits of what a city can endure. She shows places with no future, in which even young people grasp the futility of their situation, as one of her film works oppressively documents

The title of the 54th Exhibition, ILLUMInations literally draws attention to the importance of such developments in a globalised world. I am particularly interested in the eagerness of many contemporary artists to establish an intense dialogue with the viewer, and to challenge the conventions through which contemporary art is viewed.

The term ‘nations’ in ILLUMInations applies metaphorically to recent developments in the arts all over the world, where overlapping groups form collectives of people representing a wide variety of smaller, more local activities and mentalities.

54th Venice Biennale Highlights:

Allora & Calzadilla

Track and Field (2011)
More info on Allora & Calzadilla’s art installations at the Venice Benniale

Christian Boltanski: Chance

Last News from Humans in the French Pavilion
Statistical projections and not actual deaths, but I am still thinking about how to address the representation of birth and death for Venice.

Christian Marclay: The Clock

Golden Lion for the best artist at the ILLUMInations Exhibition
(United States, 1955; on display at the Corderie, Arsenale)
The Clock, 2010

Maurizio Cattelan: Others

Others. 2011
Taxidermized pigeons

Cindy Sherman: Untitled

Untitled. 2010
Pigment print on PhotoTex adhesive fabric

Yto Barrada: The Telephone Books

The Telephone Books (or the Recipe Books). 2010
“These are the notebooks of Z.A.B. She was my grandmother and was illiterate…”
Code drawings to identify family members.

Fernando Prats: Gran Sur (Great South)

Gran Sur (Great South), 2011
Antarctic Base Arturo Prat, Greenwich Island
Neon, wood structure, cable, aluminum, power generator

“Men wanted for hazardous journey. Small wages. Bitter cold. Long months of complete darkness. Constant danger. Safe return doubtful. Honour and recognition in case of success.”

The installation in neon lettering reproduces the advert that the Irish explorer Ernest Shackleton may have posted circa 1911, calling for men for his expedition to Antarctica.

The work of Fernando Prats in the Arsenale will show the powerful reality of the Chilean geography, with topics such as the earthquake and the eruption of the Chaitén volcano.

The assembly consists of three art pieces: an intervention around the impact of the volcanic eruption in Chaitén (2008); a series of works alluding to the earthquake in south-central Chile (2010); and an installation in neon lettering that reproduces the advert that the Irish explorer Ernest Shackleton may have posted circa 1911, calling for men for his expedition to Antarctica.

Ahmed Basiony: 30 Days of Running in the Space

Ahmed Basiony
1978 Cairo-2011, Egypt.
Killed during a demonstration on Tahrir Square, 28 January 2011.

On January 28th, 2011 – artist, musician and professor, Ahmed Basiony was killed with several gunshot wounds inflicted by snipers on the Friday of Wrath in Tahrir Square (The 2011 Egyptian Revolution). Ending at 32 years of age, the same period that witnessed the remaining year of Anwar Sadat’s presidency, followed by his assassination, and resulting with an Egypt held under the Mubarak Regime, Basiony was what one would consider an emblem of hope to millions of Egyptians, who were determined to live their life for change from a nationally repressed command.

Takashi Murakami: Floating Campsite

Floating Campsite. 2011
Oil painting
150 cm diameter

Future Pass explores the relationship between the creative energy of contemporary art in Asia and the rest of the world.

Yoshitomo Nara: Home

Home. 2011
Acrylic on wood board
135.3 x 123.3 cm

Manal Al-Dowayan: Suspended Together

Suspended Together. 2011
Installation, fibreglass with laminate

The doves display travel permission documents donated to the artist by many leading women from Saudi Arabia (scientists, educators, engineers, artists, etc). In order to travel, all Saudi women need a permission document issued by their appointed guardians.

The Future of a Promise examines the way in which an idea is made incarnate in a formal, visual context and how a promise opens up a horizon of future possibilities, be they aesthetic, political, historical, social or critical. With the events currently unfolding in the Middle East, the question of the future and the promise inherent within culture has assumed an even more acute degree of pertinence. It is with this in mind that the exhibition enquires into the promise of visual culture in an age that has become increasingly disaffected with politics as a means of social engagement. Whilst the artists included in The Future of a Promise are not representative of a movement as such, they do seek to engage with a singular issue in the Middle East today: who gets to represent the present-day realities and the horizons to which they aspire?

Juan Fernando Herrán: Escalas

Escalas. 2008
BIFURCACIÓN. IMPRESIÓN INKJET. 108 x 163 CMS. 2008

as imágenes fotográficas que hacen parte de Escalas revelan en primera instancia el hecho de que los habitantes de estos barrios de invasión realizan un acto de posesión territorial donde se conquista y domina la topografía. En un segundo nivel, que la conformación física del espacio público es el resultado de una serie de procesos arquitectónicos de carácter dinámico y participativo por parte de los pobladores que obedecen y son la consecuencia directa de la necesidad de construir un lugar propio que le permita al habitante participar de la noción de ciudad y de “progreso”. De esta manera, las ideas de lo público y lo privado se implican y se vuelven interdependientes. Sin embargo, dichos procesos no dejan de ser contradictorios y paradójicos. En determinadas ocasiones, el esfuerzo, la persistencia y el empeño logran su objetivo mientras que en otras circunstancias se impone la ausencia, el fracaso y la derrota. La escalera finalmente, subraya la condición de tránsito de la población y la distancia tanto física como mental entre el lugar de su morada y la ciudad, que se vislumbra como distante, ajena y referencial.

Reynier Leyva Novo: The smells of the war

Los olores de la guerra. 2009
Installation Glass bottles, perfumes
Variable dimensions

Adán Vallecillo: The physiology of the taste

La fisiología del gusto. 2010
Carious teeth and stainless steel tray
3 x 44 x 25 cm

Humberto Vélez: The Most Beautiful

La más bella. 2009
Photography on video format

Documentation of a performance realized in collaboration with the community Cristo del Consuelo from Cuenca and the community Ingapirca from Cañar, Ecuador.

Francis Alÿs uses poetic and allegorical methods to address political and social realities, such as national borders, localism and globalism, areas of conflict and community, and the benefits and detriments of progress.

Alÿs’s personal, ambulatory explorations of cities form the basis for his practice, through which he compiles extensive and varied documentation that reflects his ideas and process. As one of the foremost artists of his generation, Alÿs has produced a complex and diverse body of work that includes video, painting, performance, drawing, and photography.


Rehearsal I (Ensayo I)
2002. Two-channel video (color, sound), 12 min.

This exhibition draws on the Museum’s unique and important collection of Alÿs’s work, highlighting three recent major acquisitions—Re-enactments (2001), When Faith Moves Mountains (2002), and Rehearsal I (Ensayo I) (1999–2001)—which include video installations, paintings, drawings, collages, photographs, and newspaper clippings. These works present an investigation of methods of social action, from rehearsals and re-enactments in urban environments that address the politics of public space to large-scale communal participation where the culmination of many small acts achieves mythic proportions.

Re-enactments
2001. Two-channel video (color, sound), drawings, maps, newspaper clippings, photographs, tables, lights.

The exhibition, which is conceptually grouped around these three thematic bodies of work, also includes additional artworks that the artist has developed around the idea of rehearsal and re-enactment in relation to progress in art and everyday life.

Modern Procession
2002. Two-channel video (color, sound), 12 min.

La Malinche
1997. Oil on gelatin silver print, 9 3/4 x 6 1/2″ (24.8 x 16.5 cm).

For the ninth installment of the Performance Exhibition Series, the artists Jennifer Allora and Guillermo Calzadilla present Stop, Repair, Prepare: Variations on Ode to Joy for a Prepared Piano (2008).

For this piece, the artists carved a hole in the center of a grand piano, through which a pianist plays the famous Fourth Movement of Beethoven’s Ninth Symphony, usually referred to as “Ode to Joy.” The performer leans over the keyboard and plays upside down and backwards, while moving with the piano across the vast atrium.

The result is a structurally incomplete version of the ode—the hole in the piano renders two octaves inoperative—that fundamentally transforms both the player/instrument dynamic and the signature melody, underlining the contradictions and ambiguities of a song that has long been invoked as a symbol of humanist values and national pride.

Villanes’s works dealing with GMOs appear quite benign: seductive, highly optical creations, rather than dry, conceptual political pieces. For the past few years, the artist has been translating DNA sequences of variety of plant species into four-color patterns (which each color standing for one of the four DNA nucleobases: adenine [A], cytosine [C], guanine [G] and thymine [T]), which he later materializes as what he calls “microtextiles,” or beadworks, tiny pieces of fabric woven with thin nylon string and glass beads. The fabrics are then installed in slide mounts and either displayed on light tables or – enlarged multiple times – projected onto the walls of a gallery. The Extinction of Corn took on the latter form, presenting itself as an alluring spectacle of luminous, vibrant colors totally consuming the exhibition space.

The artist statement published in the exhibition catalogue unequivocally condemned genetic modification of living organisms and corporations standing behind mass implementation of GMOs into industrialized agriculture.

For the savvy in Peruvian society and politics, however, it evokes recent violent conflicts between the government and indigenous tribes (and specifically bloody massacre in Bagua in June 2009) over the rich in natural resources land of the selva. Neo-liberal policies, encouraging the use and industrial extraction of valuable goods, especially natural gas and water energy, by foreign corporations clash with the local way of life, dependent on the incredible nutritional and medicinal value of the immense variety of the plant species of the forest, where the bond with nature has multiple sacred dimensions. Villanes, who spent long periods of time in the jungle in the second half of the 1990s, is obviously concerned with the cultural and spiritual heritage of the local traditions and, not without a reason, extends his focus onto the issues that impact us all, regardless of the current place of residence: agriculture and food.

Through installations, photographs, and community-based projects, Jaar explores the public’s desensitization to images and the limitations of art to represent events such as genocides, epidemics, and famines. Jaar’s work bears witness to military conflicts, political corruption, and imbalances of power between industrialized and developing nations.

“I strongly believe in the power of a single idea,” says Alfredo Jaar. “My imagination starts working based on research, based on a real life event, most of the time a tragedy that I’m just starting to analyze, to reflect on…this real life event to which I’m trying to respond.”

1. Gold in the Morning, 1997

In 1985 Alfredo Jaar went to Serra Palada, an open cast gold mine in north-eastern Brazil. There he photographed and filmed the astonishing working conditions of the self-employed miners. An insistence on the importance of context to the subsequent interpretation and distribution of his work has been central to Jaar’s practice; and the Serra Palada material was initially installed on a New York subway station alongside indicators of fluctuations in world gold prices.

“I always describe myself as a project artist. I’m not a studio artist. I do not create works in my studio. I wouldn’t know what to do. I do not stare at the blank page of paper and start inventing a world coming from my imagination. Every work is a response to a real-life event, a real-life situation.”

2.  A logo for America, 1987

The representation of geography and the intricacies of global relations influence Jaar’s every thought and action.

In more recent projects, this obsession has led to critical investigations of cartography. A logo for America was an explicit demonstration of the significance of the images and language of geography – its representation and articulation. It also appropriated an amendable technology that utilized Jaar’s interest in texts, words, film processes, and graphic design. Part of a six – year program sponsored by the Public Art Fund, Inc. in New York, Jaar was one of thirty artists invited to produce a 45 – second computer animation / intervention on the Spectacolor lightboard in the heart of Times Square.

3.  One Million Finnish Passports, 1995

Finland has a historically stringent immigration policy, staunch nationalists they accept only a tiny fraction of the citizenship applications they receive, far less than any of their neighboring countries. Observing this, Jaar somehow managed to get 1 million Finnish passports printed up to represent the number of people who should have been nationalized as Finnish citizens but weren’t.  Now obviously this poses somewhat of a security risk, so the passports were housed behind a fortress of bullet-proof glass and the passports would be burned after the exhibit ended.

One million replicated Finnish passports, glass, 800 x 800 x 80 cm.

“I could say that everything I know about art, I learned as an architect. As an architect, I give myself a program, taking into account a specific space. Space is not just physical. It’s also social, cultural, political. Studying the space, I try to reach what we call the essence of the space. Then I combine that with the essence of what I am trying to say. All these elements are incorporated in the program, in which I have an objective.”

4. Infinite Cell, 2004

Iron bars, painted wood, mirrors. 145 5/8 x 177 1/8 x 102 3/8 inches.

“A mirror is a simple object of daily life, and the perfect articulation of the narcissism of our society- a society that only cares for itself. In ‘Infinite Cell’, it’s about seeing ourselves in infinite projection and thinking about what we want to do as artists, as intellectuals. What do we want to say as producers of culture? And to whom are we speaking? Am I my public, or is it someone else? It also has to do with the horrors of the twenty-first century. This piece is probably one of my most emotionally charged works. Unfortunately, it has a universal life: all countries have histories of horror. And so, in a way, this piece asks, ‘How do we make art in the world, the way it is now? How do we make art today?’”

5. The Cloud, 2000

Public intervention, Valle del Matador, Tijuana, Mexico-San Diego, USA Border. October 14, 2000.

“People describe me sometimes as a conceptual artist, as a political artist, with work of a strong political connotation or social content. I always reject those labels. I’m an artist, and believe it or not I’m interested in beauty and I’m not afraid of it. It is an essential tool to attract my audience, and sometimes I use it to introduce horror because the audience has to be seduced.”

6. The Skoghall Konsthall, 2000

Public intervention, Skoghall, Sweden.

Jaar was invited to Skoghall where he constructed a paper museum, organized a one-day exhibition, and then had the structure set on fire. The timing, temporarily, and duration of this project—as well as its denouncement—had a theatrical character.

“I was shocked to discover that a community could exist for thirty years without any visible cultural or exhibition space. How do you represent it the absence of this space for culture in an entire community? I found it hard to believe that people could live without it the intellectual and critical stimulus that visual art can provide^to question, to speculate, and to search. It blew my mind. I sought a spectacular way to deal with this lack. I created an exhibition space for twenty-four hours and then burned it away I wanted to offer a glimpse of what contemporary art is and what it can do in a community. Then by “disappearing” it in such a spectacular way, I hoped to reveal its absence”.

7. Lights in the city, 1999

In Canada Alfredo Jaar completed a project referred to as Lights in the City, in 1999.  This is a historic landmark which had burnt around five times before Jaar completed this project. The building is called Copula of the Marche Bonsecours. There were approximately a hundred thousand watts of red lights installed within the Copula so that when a button is mashed the copula lights up with a red color inside of it very brightly so that it can be seen all around the city of Montreal.

Detonating devices have been placed in multiple places such as Accueil Bonneau, la Maison Eugenie Bernier and la Maison Paul Gregoire, and homeless shelters that are located within five hundred yards of the Cupola. Each time a homeless individual enters one of these areas they are free to push the buttons located within these areas so that the Cupola will light up inside with bright red colors. The entire point of this is to allow homeless individuals to be recognized as a person within the city without humility.

“I submitted my proposal to the people at the shelters. They appreciated that I was not exposing them through photography. They liked and approved my idea. These red lights connected to the shelters were my way of sending a distress signal to the city—of making the homeless visible withcnit pointing at them directly Of course, the red hghts also recalled the fires that consumed the building many times, but metaphorically. ”

“We wanted the Cupola to become a permanent monument of .shame, and other shelters wanted to join us and get connected, but six weeks later the mayor canceled it. like all of my projects, it failed. We did not give the homeless a home. We did not resolve their problem. We gave them a brief, hopeful moment when they regained their humanity, when people started acknowledging their presence, smiled at them, when the press also contributed to the dialogue, but eventually they returned to their status as homeless. With these projects you change so little…”

Third World Identity

ART21: In her Bogotá studio, artist Doris Salcedo discusses the stereotypes she faces as a citizen of a Third World country and how she embraces these first-hand experiences of discrimination to inform her art. Shown working alongside her team of assistants, whose collective labor underscores the political messages of her sculptures, Salcedo proposes a more humble role for artists working today.

“I am a Third World artist,” says Doris Salcedo, “from that perspective—from the perspective of the victim, from the perspective of the defeated people—it’s where I’m looking at the world.” Filmed in her Bogotá, Colombia studio while preparing a series of abstract sculptures based on antique household furniture, the artist devotes careful attention to the tormented wooden finishes and smooth concrete surfaces of her objects.

La Casa Viuda I
Wood and fabric, 1992-1994

Doris Salcedo’s understated sculptures and installations embody the silenced lives of the marginalized, from individual victims of violence to the disempowered of the Third World. Although elegiac in tone, her works are not memorials: Salcedo concretizes absence, oppression, and the gap between the disempowered and powerful. While abstract in form and open to interpretation, her works serve as testimonies on behalf of both victims and perpetrators. Salcedo’s work reflects a collective effort and close collaboration with a team of architects, engineers, and assistants and—as Salcedo says—with the victims of the senseless and brutal acts to which her work refers.

“I don’t work based on imagination, on fiction,” she explains, characterizing her role as a “secondary witness” to the victims of violence whose testimonies she collects as research for her pieces, such as “Atrabiliarios” at SFMoMA, the “Unland” series of tables, the ephemeral installation “Noviembre 6 y 7,” and “Shibboleth”—a 160 meter crack in the foundation of Tate Modern in London.

Atrabiliarios (Defiant)
1992-2004; installation; shoes, animal fiber, and surgical thread

“As an artist, I have a responsibility. I have to look at historical events and work with whatever material is given to me.

The memory of anonymous victims is always being obliterated; I’m trying to rescue it. That’s why my work does not represent something; it’s simply a hint of something- trying to bring into our presence something subtle that is no longer there.”

Istanbul Biennial

ART21: Doris Salcedo discusses her installation for the Istanbul Biennial, describing how she wanted to create a “topography of war” that would transcend the specificity of historical events.

8th Istanbul Biennial, 2003
A gap in the row of buildings is filled with 1600 chairs.

Doris Salcedo’s understated sculptures and installations embody the silenced lives of the marginalized, from individual victims of violence to the disempowered of the Third World. Although elegiac in tone, her works are not memorials: Salcedo concretizes absence, oppression, and the gap between the disempowered and powerful. While abstract in form and open to interpretation, her works serve as testimonies on behalf of both victims and perpetrators. Salcedo’s work reflects a collective effort and close collaboration with a team of architects, engineers, and assistants and—as Salcedo says—with the victims of the senseless and brutal acts to which her work refers.

Shibboleth

Shibboleth (2007), a 160 meter crack in the foundation of Tate Modern in London, for which the artist enlists a Bible story as a parable for the plight of immigrants in Western societies. Reflecting on her position as an artist in a world beset with so much horror and grief, Salcedo surmises that “the word that defines my work is ‘impotence’…but then, as a person who lacks power, I face the ones who have power and who manipulate life.”

Shibboleth asks questions about the interaction of sculpture and space, about architecture and the values it enshrines, and about the shaky ideological foundations on which Western notions of modernity are built.

In particular, Salcedo is addressing a long legacy of racism and colonialism that underlies the modern world. A ‘shibboleth’ is a custom, phrase or use of language that acts as a test of belonging to a particular social group or class. By definition, it is used to exclude those deemed unsuitable to join this group.

‘The history of racism’, Salcedo writes, ‘runs parallel to the history of modernity, and is its untold dark side’. For hundreds of years, Western ideas of progress and prosperity have been underpinned by colonial exploitation and the withdrawal of basic rights from others. Our own time, Salcedo is keen to remind us, remains defined by the existence of a huge socially excluded underclass, in Western as well as post-colonial societies.

Shibboleth
(2007) a 160 meter crack in the foundation of Tate Modern in London

Shibboleth asks questions about the interaction of sculpture and space, about architecture and the values it enshrines, and about the shaky ideological foundations on which Western notions of modernity are built.

In particular, Salcedo is addressing a long legacy of racism and colonialism that underlies the modern world. A ‘shibboleth’ is a custom, phrase or use of language that acts as a test of belonging to a particular social group or class. By definition, it is used to exclude those deemed unsuitable to join this group.

Los Penetrados (The Penetrated) is a 45-minute film in eight acts. The film was originally shot on October 12 2008, Día de la Raza, or the Day of the Race, which is the Spanish holiday commemorating Columbus’ discovery of the Americas. The film features a mirrored set with ten geometrically arranged blankets positioned on the floor, on which the various possible combinations of male and female and black and white, engage in anal penetration. The faces of the hired participants are digitally removed, rendering them as dehumanized, modular workers in Sierra’s imposed economy.

Acto 1
2008, black and white photograph, 55 x 98 inches

The eight acts are divided into the following permutations: white man/white woman, white man/white man, white man/black woman, white man/black man, black man/black woman, black man/black man, black man/white woman, black man/white man.

Choosing to film on Día de la Raza, Sierra makes an allegorical connection between the conquest of the Americas by the Spanish, and the penetration that occurs in his film. The subject matter of anal sex invites an examination of cultural psychologies of domination and submission as they relate to labor, race, gender, and class. Though conceived upon a mathematical formula, the film’s acts arrive at a succession of fluctuating outcomes, which yield an analysis of contemporary social structures in Spain. For instance, in Act III, seven of the ten blankets are left without performers, due to police pressure against females taking part in the labor. Or in Act V, where the number of passive black male subjects is diminished by cultural insecurities, perhaps born from experiences of racial inequality.

160 CM LINE TATTOOED ON 4 PEOPLE
El Gallo Arte Contemporáneo. Salamanca, España. Diciembre de 2000

Sierra’s projects often employ underprivileged individuals who function as laborers in useless and demeaning activities. These acts have largely been seen as a commentary on the social ramifications of capitalist models. Procedures such as tattooing a continuous line across the backs of his “workers” foreground the artists’ concerns with exploitation.

12 WORKERS PAID TO REMAIN INSIDE CARDBOARD BOXES
ACE Gallery New York. New York, United States. March 2000

He is well known outside of the United States as an agent who challenges notions of the “politically correct” in order to illuminate social incongruities. Stemming from minimal and conceptual practices of the 60’s and 70’s, Sierra’s controversial actions and performances yield evidence and/or documentation in the form of sculpture, photography, video, and installation.

Mika Rottenberg’s immersive video installations address issues of gender and labor through outrageous narratives centered around real women (not actors or models) and their bodies. With her new video entitled Squeeze, Rottenberg collapses the humorous and the unsettling to examine global production in a 20-minute narrative that screens on a continuous loop at SFMOMA. Splicing together documentary footage from a rubber plant in India and a lettuce farm in Arizona with her own narrative of women in an absurdist makeup factory, Rottenberg’s surreal video homes in on the social realities of women’s labor.

In the makeup factory the blush source (the blond woman, dressed in an alluring outfit) is literally squeezed by walls for profit. Meanwhile, a nozzle from the wall of bare asses sprays water, and an obese woman spins on a circular floor — all to ensure that the priceless block of lettuce-rubber-blush is made to perfection.

“This piece, which is trying to collapse these geographically distant places into one space, is a natural step for me,” Rottenberg says. “It’s about using your body and being alienated from your body, objectifying your body and using it almost like a factory that can produce stuff. I feel like that’s very feminine. I’m interested in how selling one’s body can be empowering.”

Mika Rottenberg
Still: Squeeze, 2010

Jennifer Allora (American) and Guillermo Calzadilla (Cuban) have been collaborating since 1995. On October 13th they will debut new large-scale works incorporating performance at the Lisson Gallery in London.

“Hope Hippo”
2005. Mud, whistle, daily newspaper, and live person.
nstallation view: 51st Venice Biennale.

Allora & Calzadilla approach visual art as a set of experiments that test whether ideas such as authorship, nationality, borders, and democracy adequately describe today’s increasingly global and consumerist society.

“Returning a Sound”
2004. Single channel video with sound, 5 minutes 42 seconds.

Their hybridized works—often a unique mix of sculpture, photography, performance, sound and video—explore the physical and conceptual act of mark making and its survival through traces. By drawing historical, cultural, and political metaphors out of basic materials, Allora & Calzadilla’s works explore the complex associations between an object and its meaning.

Clamor
2006. Mixed-media sculpture
Installation view: The Moore Space, Miami

More info: http://www.pbs.org