Hundertwasser's Incinerator Works, Vienna
I was struck by the steampunk whimsy of this incinerator works in Vienna, designed by architect and artist Friedensreich Hundertwasser.
Most of his other work isn't very steampunk, but I liked the brass pipe, the swirling mural, and the minaret on top.
(thanks to my sister for pointing out Hundertwasser's work.)