Friedrich Stowasser (15 December 1928 – 19 February 2000), better known by his pseudonym Friedensreich Regentag Dunkelbunt Hundertwasser, was an Austrian visual artist and architect who also worked in the field of environmental protection.

Hundertwasser stood out as an opponent of "a straight line" and any standardization, expressing this concept in the field of building design. His best known work is the Hundertwasserhaus in Vienna, which has become a notable place of interest in the Austrian capital, characterised by imaginative vitality and uniqueness.