Roman aqueduct of Nîmes

The almost 50-kilometer-long aqueduct was built to transport water from the springs near Uzès to Nîmes. While earlier dating placed its construction around 19 BC, recent excavations suggest its origin in the mid-1st century AD. A central element of the aqueduct is the bridge over the Gardon River valley. After its completion, the aqueduct supplied the city of Nemausus, which then had about 20,000 inhabitants, with approximately 20,000 cubic meters of water daily. About two-thirds of the pipeline ran underground and had to be carved into the rock. The entire system had an average gradient of only 24 cm per kilometer, a precision whose calculation methods remain a mystery to this day.