The Belvedere 21 building was originally designed for the 1958 World’s Fair in Brussels by Austrian architect Karl Schwanzer (1918–1975). It was reconstructed in Vienna and repurposed as an art museum in 1962—the process made possible by its modular system and steel-skeleton structure—and again relocated and remodeled in 2011. The main exhibition hall on the ground floor is an expansive open space, and its four sides, three of which face the outdoors, are almost entirely constructed of glass. The structure’s organizing principle is the grid, through and through, down to the floor, which is paved