Swiss Re Headquarter, London

This 40-storey landmark circular tower with its now infamous shape graces the skyline of Central London. The diamond and triangular-shaped structural and glazing elements allow the smooth flow of the shape to widen in its middle and narrow towards the peak. The aerodynamic shape also assists performance – significantly reducing wind loads and maximizing natural lighting and ventilation to reduce overall energy consumption. The building, located at 30 St. Mary Axe, won the 2004 Stirling Prize. (Photos: Nigel Young/Foster & Partners)