The Hundertwasserhaus is social housing owned by the city of Vienna, finished in 1985 to designs by the painter Friedensreich Hundertwasser, who held that the straight line was godless and that a tenant should be able to lean out of a window and paint the wall around it. The building does what he argued for: floors that undulate, a facade broken into blocks of clashing colour, windows of which no two are identical, gold onion domes, ceramic columns, and some 250 trees and shrubs planted in the structure, so that branches come out of walls and the roof terraces are wooded. He took no fee for the design, and said his payment was that something ugly had been kept off the site.
People live in it, which is the part visitors forget. There is no lobby to enter and no floor to tour; you look from the pavement, and residents put up with a permanent audience at their front door. The best position is the corner opposite, where the whole tilting composition fits in one view. Across the street a former tyre workshop was converted by the same artist into an arcade with a floor that pitches like a deck.