London’s Big Ben Slowly Leaning

Experts say the famous clock tower – one of the world’s most recognizable landmarks – is gently leaning to one side. Documents recently published by Britain’s Parliament show that the top of the 315-foot tower’s gilded spire is nearly 18 inches out of line. The foundations for the clock tower were first laid in 1843 and the project was completed in 1859. The clock tower has been slightly off center since it was erected. Its position has been shifting imperceptibly for years due to environmental factors such as seasonal temperature and moisture level changes.

“We’re talking about unbelievably small movements,” said John Burland, an engineering professor at Imperial College London. Referring to Pisa’s tower; “At the present rate, it will be 10,000 years before we reach that,” he added. Even so, the tilt might now be just about visible to the naked eye. The level of movement northward has been less than 1 millimeter a year since experts began measuring it in the 1970s, Burland said. In the 1990s, the construction of a London Underground line affected the clock tower’s foundations and added a small amount of movement to that natural shift, he said. But most of the tilt took place during the first years when the tower was being built, likely due to non-uniform ground conditions, Burland said.