The Italian city of Bologna is preparing for one of its iconic towers, built more than 900 years ago, to collapse due to excessive leaning. 

The Tower of Garisenda, twinned by the nearby Asinelli Tower, is one of Bologna’s hallmark sights, standing at just over 150 feet tall. But it has been leaning since at least the 14th century when the top 32 feet of the building were removed in an attempt to stabilize it.

The tower is currently leaning at an angle of 4 degrees, slightly less steep than the famous Tower of Pisa‘s 5 degrees. Local authorities have carried out extensive work to maintain the integrity of the tower over the years.

In October, the local authorities decided to fence off the area surrounding the tower for the safety of the public and build a structure to protect other buildings in the event the tower does collapse.

“A new report by experts states the tower is at great risk of falling, so we need to be ready for every eventuality,” a city spokesman told London’s The Times.

Experts have had concerns about the integrity of the tower since 2022, according to local media. But it wasn’t until October 2023 that sensor readings, which measure the movements of the ancient towers, triggered alarms and forced the urgent shutdown of the area around the tower, with traffic on the roads around it temporarily halted.

There appears to be no clear consensus on when the tower will collapse, whether in the near or distant future.