VENICE, ITALY - AUGUST 11: Gondoliers navigate through traffic as they transport tourists along a tightly packed canal near the Rialto bridge on August 11, 2011 in Venice, Italy. Italian heritage conservation group Italia Nostra has warned that the large number of tourists visiting the lagoon city daily is contributing to the gradual destruction of its ecosystem as they look to implement a cap on numbers. The group claims the city is facing an irreversible environmental catastrophe as the subsequent increase in water transport has caused the level of the lagoon bed to drop over time. (Photo by Marco Secchi/Getty Images)
