Leaning Tower of Pisa, Italy
The Leaning Tower of Pisa is the campanile, or freestanding bell tower, of Pisa Cathedral, known for its nearly four-degree lean due to an unstable foundation. The building is one of three structures in Pisa’s Cathedral Square (Piazza del Duomo), including the cathedral and Pisa Baptistry.
The tower is 55.86 meters tall from the ground on the low side; its weight is estimated at 14,500 tonnes (16,000 short tons). The tower began to lean during construction in the 12th century due to soft ground, which could not properly support the structure’s weight and worsened through the rest of its construction in the 14th century.