museum hundertwasser in kunst haus wien in vienna, austria. ecological commitment concept– grass roofs and planted trees in

apartment architecture art artist austria bright building cafe city color colorful construction decoration design environmentalism europe exterior facade famous features floors forms friedensreich green heritage house hundertwasser hundertwasserhaus irregular kunsthauswien landmark modern mosaic museum natural outdoor painted plant residential roof shop showplace sightseeing street tourism travel trees undulating urban vienna