City Hall is the headquarters of the Greater London Authority (GLA) which comprises the Mayor of London and London Assembly. It is located in Southwark, on the south bank of the River Thames near Tower Bridge. 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, purportedly intended to reduce its surface area and thus improve energy efficiency, although energy use measurements have shown this building to be fairly inefficient in terms of energy use. It has been compared variously to Darth Vader's helmet, a misshapen Egg, a woodlouse and a motorcycle helmet.
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