Construction began on the bell tower of Pisa Cathedral in 1173, but three stories into the job, architects Guglielmo and Bonnano Pisano called off the work when it became apparent the structure was leaning distinctly. A century later Giovanni di Simone resumed the job, having quite literally gone back to the drawing board, and tried to compensate for the lean by making successive layers taller on one side than the other, creating a slight banana shape. Over the centuries engineers have poured concrete into the foundations and tried other solutions in vain, and by the late 20th century the tower was in serious danger of collapse. The tower was closed and braced with cables as crews removed more than 70 tons of earth from beneath the structure, allowing it to slightly right itself as it settled. With lean of just 4m (13 ft.), compared to a precarious 4.6m (15 ft.) before the fix, the tower has been deemed stable for now and safe to climb once again. But before you do, take time to notice just how lovely the multicolor marble tower is, with eight arcaded stories that provide a mesmerizing sense of harmony as you look up its height.

The only way to climb the arcaded tower is to book a visit in the office on the north side of the piazza—or for peak season, online well in advance. Visits are limited to 30-minutes, and you must be punctual for your slot or you’ll lose your chance to climb the 293 steps. Children under 8 are not permitted to climb the tower, and those aged 8 to 18 need to be accompanied by an adult (8–12s must hold an adult’s hand at all times). Leave bags at the cloakroom next to the ticket office behind the cathedral.