Guangzhou Opera House, China

Zaha Hadid's Guangzhou Opera House (2010) consists of two pebble-like structures — a 1,800-seat auditorium and a 400-seat multi-function hall — whose flowing biomorphic forms were inspired by the erosion patterns of riverbeds. Its complex double-curved surfaces required entirely new approaches to glass cutting and stone cladding, making it one of the most technically challenging buildings of its decade.