MAS, Antwerp, Belgium

Opened in 2011, MAS is a 10-storey complex that redefines the idea of a museum-gallery. Floors are designed around big-idea themes using a barrage of media, from old master paintings and tribal artefacts to video installations. But many people come just for the views over the city (no ticket required), which transform as you climb somewhat laboriously by a series of escalators and three flights of stairs (no public lifts).