Between 1919 and 1933, the Bauhaus revolutionized prevailing ideas about architecture and design, and the construction methods associated with them. The architecture of the Bauhaus itself was equally innovative; the buildings conceived by Walter Gropius and Hannes Meyer had a lasting influence on the architecture of the 20th century. To celebrate and preserve this legacy, the Bauhaus buildings in Weimar and Dessau were named UNESCO World Heritage Sites in 1996. More recently, UNESCO added several other Bauhaus buildings to the list, including the houses with balcony access in Dessau, the ADGB Trades Union School in Bernau, the Haus am Horn and the old Art School and the old School of Arts and Crafts in Weimar. Bauhaus World Heritage Site documents the Bauhaus buildings protected by UNESCO, exploring the architectural legacy of the Bauhaus through a close look at the school's own architecture.