The bottini are the underground water-conveyance system used in Siena until a few decades ago. Construction began in the thirteenth century and was practically completed by the end of the fourteenth century. Water flowed by gravity down the network of about 16 miles of underground tunnels. It was then purified in settling tanks and filters before flowing out to the public fountains.

In the fifteenth century, engineers sought to increase the supply of water to the public fountains.

The bottini are an extraordinary undertaking that required state-of-the art hydraulic expertise, personified by Taccola and Francesco di Giorgio. The latter was, for many years, the official contractor for the system.