Installation art describes three-dimensional works that are often site-specific and designed to transform the perception of a space. Some key developments include Johannes Baader presenting one of the first installation works at the 1920 International Dada fair in Berlin. In 1942, Marcel Duchamp created "Mile of String," and in 1963 Nam June Paik first used video in an installation. Installation art can involve land art that links the landscape to the work, interactive art that involves the spectator, or art interventions that interact with existing artworks or spaces. Examples provided are works by Damien Hirst, Mark Bridger, Robert Smithson, Hannes Broecker, and installations by Yoshitomo Nara and Suh Do