Pont du Gard - Rome's greatest party trick

There are ancient monuments, and then there is the Pont du Gard: a structure so impossibly perfect it almost seems like a trick. Built around AD 50 without mortar, this three-tiered Roman aqueduct soars 49 metres above the Gardon River and carried 40,000 cubic metres of water daily to the Roman city of Nîmes along a 50-kilometre channel that descends just 17 metres in total. That is an engineering gradient of roughly 24 centimetres per kilometre. Standing in the riverbed below and gazing up at 52 arches, the scale is genuinely awe-inspiring in a way photographs simply cannot convey. Book the guided walk to the top-tier aqueduct channel (available six times daily to small groups) and crouch through the very conduit the water flowed through two millennia ago. The excellent museum on the left bank (rive gauche) traces Roman daily life with wit and intelligence. In summer, kayak or swim under the bridge for the most spectacular perspective of all. ✦ Tip: Arrive early: follow 'rive gauche' signs for the main visitor centre and museum. Avoid parking charges by buying combined museum-parking tickets online in advance.