Leaning Tower of Pisa, Italy（意大利比薩斜塔）

The world-famous Leaning Tower of Pisa ranks second on this list. It is a bell tower of the Cathedral of the Italian city of Pisa, known for its unintended tilt to one side. The construction of the tower began in 1173. However, only five or six years later, the tower began to tilt to the southeast, caused by an inadequate ground foundation – basically one that proved too soft on one side. Upon its completion in 1372, the tower was only bowing down some 4.5 feet downwards. As time passed by, the angle of the 16,000-ton tower has become more precarious.