Pieter Bruegel’s Tower of Babel, image by Kunsthistorisches Museum

The Kunsthistorisches Museum in Vienna presents its masterpieces in public. In Vienna, on about 29 busy locations – subway stations, railway stations, house walls – the museum is showing treasures from the collection: Pieter Bruegel’s Tower of Babel, Raffael, Lucas Cranach and much more. The campaign should bring the museum back to the people’s mind.

Parmigianino, Amor,at Rüdigergasse, image by Christoph Wassmann

Lucas Cranach, Judith und Holofernes, at Hütteldorferstrasse, image by Christoph Wassmann

This is an example of how architects uses art in their job.
Needless to say, the paintings are copies.
Source: http://www.an-architecture.com/2009/11/public-art.html