Why is the Tower of Pisa leaning?

A bell tower was built in the town of Pisa, Italy in 1174 near a church in Cathedral Square.  It was supposed to be eight storey’s high, about 185 feet tall.  However, after the third floor was completed, the building started to sink in the marshy unstable soil.

As they continued construction, workers tried to compensate for the lean by making the new storey’s slightly taller on the short side.  Inevitably, the extra construction material made it sink even more.  Since that time the tower has leaned a little bit more each year.  Today the 185 foot tower leans at a 10-degree angle and is now about 17 feet out of perpendicular.

The 800 year old tower looks like it defies the laws of gravity and is a popular tourist attraction.  More than 700,000 tourists climbed the 300 steps to reach the top in 1989, but no visitors have been allowed to climb since then as it was deemed necessary for safety reasons.

There are seven bells in the tower and they are tuned to a musical scale.  The largest bell weighs three and half tons and the oldest bell is named Pasquarreccia.