Two men walk on the Pisa's Cathedral Square in central Pisa, Italy on Aug 19, 2011. Pisa's Cathedral Square is home to four of the greatest architecture styles of medieval times: the Duomo (cathedral), the Campanile (the Leaning Tower of Pisa,) the Baptistry and the Camposanto (cemetery.) Pisa's Cathedral Square was declared a UNESCO World Heritage site in 1987. [Photo/Xinhua]