Black geopmetric shapes by Simek in Athens, Greece.
Giant snails by Fra-Biancoshock.
2 loooong walls by SLAK from Russia. Direct links to the hi-res pix: 2012 wall + 2011 wall.
Clemens Behr from Berlin visited NYC last june. Here are some of his street work. Check also Clemens Behr’s spectacular indoor cardboard installations on his website.