Reflections of Rome by PatKofahl

The bridge of the Pont du Gard has three tiers of arches, standing 48.8 m (160 ft) high. 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. The aqueduct formerly carried an estimated 200,000 m3 of water a day to the fountains, baths and homes of the citizens of Nîmes.~ Wikipedia