If you have dreamed of seeing a perfectly straight Leaning Tower of Pisa, you may need to exercise some patience. Following a major restoration completed in the early 2000s, the famous campanile continues to slowly reduce its tilt—by about 1–2 millimeters per year. According to engineers, the tower is in excellent condition and remains stable.
The most ironic thing about this story is that the cause of all the problems was simultaneously the tower’s savior. The tower began to tilt almost immediately after construction started in the 12th century due to overly soft ground and a shallow foundation. Builders tried to fix the situation by making the upper floors slightly higher on one side, but this only gave the structure its characteristic curved shape. Yet, that very soft soil helped the tower survive several strong earthquakes centuries later. Researchers believe that thanks to the soil’s unique properties, the ground vibrations do not resonate with the structure.
In 1990, the tower was closed to visitors when its tilt neared a critical point. A decade-long restoration, costing around €30 million, reduced the lean by almost 40 centimeters. Now, engineers simply monitor the structure as it continues to subtly return to a more stable position.
