August 9, 1173 (June 29) Kimi, Italy's famous Leaning Tower of Pisa broke ground. Pisa cathedral bell tower construction


began in August 1173, the projects have been intermittent the two for a long time, after about two hundred years before completion. August 9, 1173, when the construction of the design is erected vertically, and the original design layer 8, 54.8 meters high, it is a unique white flash of medieval buildings, even though there is no tilt, will also be in Europe most noteworthy one of the bell tower. the, when When Zhong Louxing built to Layer 4
1185, leading to the bell tower has been tilted partial to southeast, therefore suspend the project due to uneven ground and soft soil. During 1198, documented the presence of ringing bells in the belfry This indicates that although the clock tower tilt, but at least the hoisting of a ringing bells to realize it as the original intention of the bell tower.
1231, engineering continue the first records Clock Tower marble. Builders take various measures to correct tilted to deliberately tilt of the clock tower the upper structures into the opposite direction in order to compensate for the displacement of the center of gravity has occurred. Progress to Layer 7 in 1278, the tower is no longer linear, but is concave. Engineering again suspended. (Lssdjt.cn)
1292, Giovanni Pisano plumb line measurement of the inclination of the clock tower.
1360, stalled after almost a century bell tower to be completed to start the last sprint, and made the last major correction. Placed in the top of the bell for completion in 1372. The 54-meter-high eight-story bell tower has a total of seven minutes and did not hit, but the danger of collapse due to the clock tower moment has rung.