This year's 7th Berlin Biennale, which opened on April 27 and runs until July 1, focuses on political art and includes exhibitions connected to the Holocaust alongside Israeli and Palestinian works.

One of the highest-profile shows is Berlin-Birkenau, an exhibition by Polish artist Lukasz Surowiec, who took hundreds of birch trees from the area surrounding the Auschwitz-Birkenau camp and planted them around Berlin. The trees, called "Birke" in German, lent their name to the death camp.

Mr Surowiec said: "With the help of nature, I try to … deepen the memory of the victims of the Holocaust." Also on show is Zamach (Assassination), a video project by Israeli artist Yael Bartana which portrays the activities of the Jewish resistance in Poland. Palestinian artist Khaled Jarrar created 20,000 "State of Palestine" postage stamps to express his support for the right of the Palestinians to an independent state.