(WYTV) – The Leaning Tower of Pisa, a bell tower, is more than 800 years old.
Construction began in 1173 and was done some 200 years later. Workers had to postpone construction twice to let the ground settle.
The Tower is built on a marsh — a thin layer of silt on top of soft clay.
It’s 187 feet tall, eight stories.
Inside the tower, there are seven bells. Each bell represents one note of the musical scale.
It leans because of the water table. That’s a layer of water underground on the north side of the Tower rose up to a foot higher during Pisa’s rainy season.
It boosted the land on the north side, pushing the Tower to lean south.
Engineers have put in a special drainage system, removed some soil and fastened weights to stop the tilt. It was about one to two millimeters a year.
It remains at a four-degree tilt — 13 feet past the vertical.
Engineers say the famous tower will lean for at least another 200 years.
It may even stay upright forever.
Pisa is from an old Greek word meaning marshy land.