Leaning Tower of Pisa

It is the favorite tourist attraction in Pisa city, Italy. It was started to build in 1173 that means the foot of the tower. After a while the war with Florence started again and they stopped. In 1180 the restarted and in 1185 they had finished the 1st, 2nd, and the 3rd. floor. And again war with Florence. In this year the tower started to lean to one side, so while they were building, it was already the leaning tower of Pisa. They started again for a period of nine years, from 1275 till 1284 but it still was not completed until 1319. They finished all the floors and finally they put the bell tower on top of it in 1350. In 1392 Pisa was sold to Florence, a big humiliation for the people of Pisa. Although intended to stand vertically, the tower began leaning to the southeast soon after the onset of construction in 1173 due to a poorly laid foundation and loose substrate that has allowed the foundation to shift direction. The tower presently leans to the southwest. I’ve heard that Galileo Galilee is said to have dropped two cannon balls of different masses from the tower to demonstrate that their speed of descent was independent of their mass.
In May 2008, after the removal of another 70 metric tons (77 short tons) of earth, engineers announced that the Tower had been stabilized such that it had stopped moving for the first time in its history. They stated it would be stable for at least 200 years.