History of the Leaning Tower of Pisa

The Leaning Tower of Pisa is one of the wonders of the ancient world. It is located in Campo dei Miracoli (field of miracles) in the Italian city of Pisa and is 55.863 meters in height. It is a freestanding bell tower. It is not clear who the actual designer was. The Tower was designed to be vertical and started to incline during its construction. It leans at an angle of 3.97 degrees. It has fine mosaic pavements, elaborately carved columns and numerous bas-reliefs. It is made up of white marble. It is a famous tourist attraction and gives a panoramic view of the city.

In 1172, a wealthy Italian widow named Berta di Bernardo left 60 cents in her will to purchase stones and construct a bell tower. The construction of the first floor began on August 9, 1173 AD. The tower began to sink after the construction reached the third floor in 1178. This was caused because the tower had only a three-meter foundation set in weak, unstable subsoil. Construction of the tower was halted for almost a hundred years since the Pisans were engaged in wars with Florence, Genoa and Lucca.

In 1182, the ‘Opera Campanilis petrarum Sancte Marie’ (Stone Works of bell tower of Saint Mary) was established. In 1185, probably there was an interruption at the height of the fourth order.

Giovanni di Simone restarted the construction in 1272. In 1292, Giovanni Pisano measured the inclination of the tower with a plumb line. The final two floors of the tower were added between 1319 and 1350. In 1360 Tommaso Pisano completed the construction, erecting the belfry and making the last important geometric correction of the structure.

In 1372, the bell chamber was attached to the top. In 1838 a walkway was dug around the tower so that visitors could see its carefully crafted base, which increasingly began to lean. In 1934, an Italian engineer drilled three hundred sixty-one holes into the base and filled them with mortar which led to the tower leaning over some more.

During the Second World War, the German Nazis used it as an observation post. In 1993, 650 tons of lead were hung from the North side of the building, which for a while stopped the leaning from increasing. In 1987, the tower was declared as part of the Piazza dei Miracoli UNESCO World Heritage. In 1995, an attempt was made to expand the foundations under the South side of the building. The ground was frozen using liquid nitrogen, to stop it from moving. Stones were removed from the tower in order to insert metal rods. It was not known that the removed stones were part of the original foundation of the building. In one night the towers leaning increased as much it normally would over 2 years. 250 tons of lead were quickly added. A British engineering professor came up with the idea of removing ground soil from under the high side of the tower instead of trying to strengthen the low side by adding to its foundatione. Work began in 1999 and was done extremely slowly so that the tower wouldn’t get a sudden shock. The work was completed at the beginning of June 2001 and the tower had been straightened by about 16 inches, which was its position way back in 1838. In May 2008 after the removal of 70 tonnes of earth the tower had been stabilized. The engineers estimated that the tower would be stable for at least 200 years.

No wonder, The Leaning Tower of Pisa has a prominent place in the "must-see" list of the tourists. So when are you going to visit the famed attraction? Happy sight seeing.