Tower Bridge and Town Hall

City Hall is the headquarters of the Greater London Authority and the Mayor of London. It stands on the south bank of the River Thames near Tower Bridge. Designed by Norman Foster, it opened in July 2002.

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 human scrotum, a woodlouse or a motorcycle helmet. Mayor Ken Livingstone referred to it as a "glass testicle"[1][2]. 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 on conventional terms but derives its shape from a modified sphere.
source : Wikipedia