Piet Mondrian painting was hanging upside down for 77 years, museum curator says

A painting by Dutch abstract painter Piet Mondrian has been hanging upside down for 77 years, says a curator at the German museum.

A large retrospective of the avant garde artist's work went on display Saturday at the Kunstsammlung museum in Dusseldorf, and one of the pieces on show is "New York City 1," painted in 1941.

But as she prepared for the exhibition, curator Susanne Meyer-Buser discovered the painting had been presented to the public rather differently from how it was perhaps intended to be on show.