This bridge and aqueduct spans the gorge of the Tessino river between the Colle di Sant’ Elia (on the left) and Monteluco.  It originally provided water for the Rocca and the upper part of the city.  No documents exist that throw light on its original construction, but was probably built at the same time as the Rocca by Matteo di Giovannello, il Gattapone.

The bridge, which is built of local stone, comprises ten arches.  Its central arch is some 76 meters high.  The pillars to the sides of it are actually hollow towers, and these probably give the structure its name.  They have doors and windows, and were probably used as guard posts.