Renowned Cuban artist Tania Bruguera surprised a Bogota audience in September when she lined up three people directly involved in the Colombian conflict for a chat. The real performance however, started when a waitress emerged with a tray of neatly organised lines of cocaine, and began offering them to members of the audience. Read more and see the video...

Better to employ an enormous grey wall for artistic purposes than leave it a towering eyesore? Palestinians and foreigners alike have been painting the Israeli government's separation wall since construction began. But on both the Israeli and the Palestinian sides of what has been dubbed "the wall of shame", there are those who don't want it to be coloured in, and for very different reasons. Read more...

Julio López disappeared on his way to one of the final hearings in the trial of the man who ordered his detention and torture during Argentina's brutal military regime. Three years later, and the 80-year-old bricklayer is still missing, for the second time. He has not been forgotten however; his face can be seen all over Buenos Aires, in stickers, paintings, and stencils. Read more...

This is an artist's impression of the second trial of Mikhail Khodorkovsky. Once Russia's richest man and a potential opponent of then president Vladimir Putin, his imprisonment six years ago could now be extended until well after 2035. To publicise the event, almost 40 Russian artists filed into court to compete in illustrating the case. See more...

Photo by Choque.

Brazilian media can’t decide whether these graffiti are the work of artists or of delinquents. But for their authors, “pichaçao” is all about living dangerously. Read more and view the photos…

These are the works of a young Iranian woman, convicted of murder at the age of 17, who spent her days on death row painting. Christened "The prisoner of colours", Delara Darabi, who protested her innocence after she was sentenced, was hanged in Rasht prison last Friday. This is her story in images...

Chinese bloggers have been locked in a bitter dispute over the sale of two bronze relics stolen a century ago by French soldiers. The bronzes fetched €15.7 million each at this week's Yves Saint Laurent auction in Paris. While some demand their immediate return, others recognise they were better preserved in France. Read more and view the Chinese cartoons…

For a year now, elusive character "Poster Boy" has been busy in the tunnels of the New York subway, hacking up unsuspecting victims with a razor blade. His prey? Posters, which he mutilates right under the nose of the police. Read more and see the pics...

Webusers are puzzled over photos of an enormous green skull and crossbones projected onto the Russian Houses of Parliament, which appeared last week. A terrorist threat? A music file-share warning? One of our Observers found out who did it, and asked them why. Read more...

Built in the early eighties, these extraordinary sea-view homes are known as the "UFO houses" by the Taiwanese. Just 15 kilometres from the capital, the deserted residences have been left abandoned for the past three decades. Now they face imminent demolition. Read more and see photos...