It is impossible to find this bell tower for those who don't know where to look. Between street numbers 1 and 3 in Vicolo Santa Caterina, there is a gate that shows the small apartment building garden. There, between houseplants and watering cans, stands a Romanic bell tower.

Probably it was built in 1329 in a simple Romanic style, made of bricks with its mullioned windows. The bell tower and its Santa Caterina D'alessandria Church stayed together from the 14th century until the 18th century when a baroque craving hit the whole city and forced all the churches to a re-styling. Santa Caterina Church was rebuilt from 1726 to 1762, but the bell tower at the back of the complex was left untouched.

Over the decades, the whole church was surrounded by houses. From the 1950s to 1960s the city's zoning plan allowed a number of apartment buildings to be built, imprisoning the tower. It still stands there today, seen only by the tenants and completely invisible to passers-by.