This astonishing museum, with its brightly coloured façade and trees protruding from the windows, was designed by Friedensreich Hundertwasser, artist, painter and engraver known for his colourful, utopian visions - and his works occupy two storeys of the museum. The two other floors are given over to temporary exhibitions. Located a few streets away, the façades of Hundertwasser House built in 1984 (Kegelgasse 36-38) are worth a visit if you are a fan of the artist's work.