Underneath the narrow streets, churches, and palaces of the Italian city of Siena lies a sprawling network of underground aqueducts that supplied water to the Tuscan city for centuries, enabling it to flourish despite a chronic lack of nearby rivers and streams. Extending for roughly 25 kilometers, the so-called Bottini constitute an ingenious hydraulic system that sustained the city from the Middle Ages until the early 20th century.

Fountain Fontebranda, its waters fed by Bottini. Credit: Wikimedia Commons