A leaning tower is a tower which, either intentionally, due to errors in design, construction or to subsequent external influence, does not stand perpendicular to the ground. This list is about these unusual buildings. As a start, here is an infographic a structural engineer can get behind: leaning towers. The Economist provides this nice visualization of several famous cases. For example, Big Ben is leaning north-west by 0.26 degrees, or 17 inches and Germany’s Leaning Tower of Suurhusen is at an angle of 5.19 degrees. We will enumerate several more cases... Read on to learn more about each leaning tower.
# Two Towers of Bologna, ItalyThe Two Towers, both of them leaning, are the symbol of the city. The taller one is called the Asinelli while the smaller but more leaning tower is called the Garisenda. The taller Asinelli Tower is built in the 10th century. It is 97 m (318 ft) high with a 2,23 meter (7,3 ft) inclination The base was modified in 1488 to house guards. The smaller is Garisenda Tower, a contemporary of its neighbor. Its strong inclination (3,22 m or 10,6 ft) is striking, caused by an earlier greater settling of the land.
# Big Ben, London, UKThe British Parliament's Clock Tower (more commonly known as Big Ben) is leaning north-west by 0.26 degrees, or 17 inches (43.5cm), according to documents that were recently made public. The level of the tilt has increased to 0.9 millimeters a year since 2003, and it seems that underground developments including a parking lot and an extension of the London Underground have caused the problem.
# Leaning Church Tower of Suurhusen, GermanyThe Leaning Tower of Suurhusen is a late medieval steeple in Suurhusen, a village in the East Frisian region of northwestern Germany. According to the Guinness World Records it was the most tilted tower in the world, though in 2010 the newly erected Capital Gate tower in Abu Dhabi claimed this record. The Suurhusen steeple remains the world's most leaning tower that is unintentionally tilted, beating the world-famous Leaning Tower of Pisa by 1.22 degrees.
# Bad Frankenhausen Church Tower, GermanyThe central German spa town of Bad Frankenhausen is home to a tower more crooked than Pisa's. The sinking phenomenon was first observed in 1650, and has been progressing steadily ever since. The tower is perched on a hillside on the edge of town and looks like it could keel over in a stiff breeze. Locals insist the structure is sturdy and say no one has abandoned the row of tidy homes sitting about 75 feet (23 m) from the tower's base. At least not yet. Engineers have noticed that the speed with which the tower is falling has picked up recently, with the spire now moving 2.4 inches (6 cm) a year. At that rate, it could reach a tipping point in the next decade or so. Local and state government officials have agreed to spend $1.5 million to try to stabilize the tower.
# Leaning Tower of Pisa, ItalyThe Leaning Tower was supposed to stand straight and plumb, an imperious monument to the trading power of 12th century Pisa. Built on soft clay, however, the tower began to list only a few years after construction began. Upon completion in 1350, the tower leaned about four and half feet, but as time passed, the angle of the 16,000-ton tower became more precarious. By 1990, the tower leaned about 13 feet (4 m) off kilter, and nearly two million pounds of lead ingots had to be placed on one of its sides to prevent its collapse. But the nearest the tower has been to destruction had nothing to do with its famed tilt. Allied forces ordered an American sergeant to blow it up during World War II when they thought the Germans were using it as an observation post. Only the reticence of the 23-year-old American saved the tower.
# The Leaning Tower of Nevyansk, RussiaThe Leaning Tower of Nevyansk is leaning tower situated in the center of Nevyansk and the most well-known building in the Middle Urals. It was funded by Peter the Great and built in the first half of 18th century by a famous Russian manufacturer Akinfiy Demidov. The height of the tower is 57.5 m (189 ft) from the ground. According to recent measurements, the deviation of the top part of the tower from a right angle is currently 2,20 m (7,2 ft). The exact date of the tower's building is unknown, different historical sources mention dates between 1721 and 1745.