Toronto developer’s intervention raises questions about the practice of preserving street art

Commissioned works will explore Nazi loot and "riddle of German history"

Exhibition opens this week with catalogue foreword by former chief executive of BP who kept his sexuality a secret until 2007

Katerina Gregos is the curator of the new biennial due to open in 2018

Pop artist, who has died aged 83, told us ahead of his 2003 Guggenheim retrospective about subverting New York billboards as a young man

The Austrian dealer will open his London gallery with work by the great German conceptualist, whose auction prices do not reflect his international stature

But then they did include Gustav Klimt, his Lady in Gold and his lover

The curator Christine Tohme broadens the event’s potential audience by also taking it to Dakar, Istanbul, Ramallah and Beirut

The many cultural initiatives of Olivetti’s and Fiat’s arts director

Rediscovered work from the 20th century has new relevance today

Paris contemporary art centre in negotiations to open space after setback ten years ago