Announced in May, the 2012 Serpentine Pavilion designed by Herzong & de Meuron and Chinese artist Ai Weiwei is now officially complete. The trio have not worked together since the Birdcage at the Beijing Olympics and fittingly this structure is part of London's London 2012 Festival. With a plane of water floating above, visitors are invited to sneak underneath the surface and explore. The venue will host talks and other events through October 14, 2012. [Dezeen]