The Pont du Gard (English: Bridge of the Gard) is an ancient Roman aqueduct bridge that crosses the Gardon Rive in southern France. It is part of the Nîmes aqueduct, a 50 km-long (31 mi) structure built by the Romans to carry water from a spring at Uzès to the Roman colony of Nemausus (Nîmes). Built in the 1st century AD, the Pont du Gard is the highest of all Roman aqueduct bridges and is the best preserved with the Aqueduct of Segovia. It was added to UNESCO's list of World Heritage Sites in 1985 because of its historical importance.
The whole aqueduct descends in height by only 17 m (56 ft) over its entire length, while the bridge descends by a mere 2.5 cm (0.98 in) – a gradient of only 1 in 3,000 – which is indicative of the great precision that Roman engineers were able to achieve using only simple technology. It was constructed entirely without the use of mortar and the aqueduct's stones -- weighing up to six tons -- were precisely cut to fit perfectly together eliminating the need for mortar.
