A woman walks past graffiti of revolutionary hero Ernesto "Che" Guevara and a Cuban flag by Mexican artistic group ASARO for the 12th Havana Biennial, in Havana, May 28, 2015. Photo: Enrique de la Osa/Reuters.

A woman walks past graffiti of revolutionary hero Ernesto "Che" Guevara and a Cuban flag by Mexican artistic group ASARO for the 12th Havana Biennial, in Havana, May 28, 2015. Photo: Enrique de la Osa/Reuters.