Avenida 9 de Julio is the widest avenue in the world. It is famous for the Washington Monument-like structure called Obelisco (just outside the view of this photo). On December 1, 2005, a giant condom was placed on the monument to commemorate World Aids Day:
http://en.wikipedia.org/wiki/File:Condom_on_Obelisk,_Buenos_Aires.jpg