where is the pont du gard bridge located
The aqueduct bridge is part of the Nîmes aqueduct, a 50-kilometre (31 mi) system built in the first century AD to carry water from a spring at Uzès to the Roman colony of Nemausus (Nîmes). Because of the uneven terrain between the two points, the mostly underground aqueduct followed a long, winding route that called for a bridge across the gorge of the Gardon River. The bridge has three tiers of arches, stands 48.8 m (160 ft) high, and descends a mere 2.5 centimetres (1 in) -- a gradient of only 1 in 18,241 -- while the whole aqueduct descends in height by only 12.6 m (41 ft) over its entire length, which is indicative of the great precision that Roman engineers were able to achieve using simple technology. The aqueduct formerly carried an estimated 40,000 m (8,800,000 imp gal) of water a day to the fountains, baths and homes of the citizens of Nîmes. It may have been in use as late as the 6th century, with some parts used for significantly longer, but a lack of maintenance after the 4th century led to clogging by mineral deposits and debris that eventually choked off the flow of water.