This is a photo of London City Hall, the the headquarters of the Greater London Authority (GLA) which comprises the Mayor of London and London Assembly. It is located in Southwark, stands on the south bank of the River Thames near Tower Bridge (in the background). It was designed by Norman Foster and opened in July 2002, two years after the Greater London Authority was created.
The building has an unusual, bulbous shape, intended to reduce its surface area and thus improve energy efficiency. It has been compared variously to Darth Vader's helmet, a misshapen egg, a woodlouse and a motorcycle helmet. Former mayor Ken Livingstone referred to it as a "glass testicle", while the present mayor, Boris Johnson, has referred to it as "The Glass Gonad" and more politely as "The Onion". Its designers reportedly saw the building as a giant sphere hanging over the Thames, but opted for a more conventionally rooted building instead. It has no front or back in conventional terms but derives its shape from a modified sphere.
A 500-metre helical walkway, reminiscent of that in New York's Solomon R. Guggenheim Museum, ascends the full height of the building. At the top of the ten-story building is an exhibition and meeting space called "London's Living Room", with an open viewing deck which is occasionally open to the public. The walkway provides views of the interior of the building, and is intended to symbolise transparency; a similar device was used by Foster in his design for the rebuilt Reichstag (parliament) in Germany.