21er Haus, a modernist steel and glass building, is part of the Österreichische Galerie Belvedere museum complex. It primarily houses exhibitions of contemporary art that focuses on Austrian art of the 20th and 21st centuries and its setting in an international context. Here are collected works by, among others Luciana Fontana, Andrea Fraser, Marcus Geiger, Franz West and Heimo Zobernig.
Pavilion 21er Haus was built in 1958 by the Austrian architect Karl Schwanzer. Originally, it was to serve as a temporary pavilion at the World Exhibition in Brussels in 1958. Later he was transferred to Vienna, where he was nicknamed "20er Haus" for the first time because it contained 20th-century art. In the years 2009-2011 it was rebuilt by the architect Adolf Krischanitz, and its name was changed to "21er Haus", which reflects the 21st century.