The Leaning Tower of Pisa

The Leaning Tower of Pisa, in Pisa, Italy, is famous because it looks like it might fall over.

This circular bell tower stands next to Pisa’s cathedral. It is 187 feet high and has 8 floors. Over 293 steps lead to 7 bells at the top. The outside is decorated with arches and columns.

Construction began in 1173. After the first three floors were finished in 1178, the tower leaned to the north. Construction then stopped until 1275 because Pisa was at war. The next three floors were built even with the ground, instead of the bottom floors, to try to correct the lean. When they were finished about 1319, the tower leaned to the south. The last two floors were added about 1350.

During the long building delays, the tower’s weight compressed the ground under it. This strengthened its base enough to keep it from falling, but it still leaned a bit more each year. The tower leans because it is too heavy for the ground it is built on. The uneven layers of soft sand and clay beneath it have caused the tower to sink more in certain places.

Over the years, the tower became a symbol of Italy and an important tourist attraction. Several attempts were made to straighten the tower, but some just made it worse. By 1990, the top floor leaned 17 feet to the south. 

In 1990, the government closed the tower to the public and began a 10-year effort to stabilize it. International experts tried different solutions but nothing worked. Then, in 1999, a British engineering professor suggested that soil be removed slowly from the high side so that the tower could settle back into the ground. This worked and, by 2001, the tower was 16 inches straighter. Experts believe it is now safe for another 300 years.

The tower re-opened to the public in June 2001.