Pont du Gard is part of a giant water system spanning 50 kilometers and crossing the Gardon river. This construction in its magnitude surpassed everything that was known at the time and was very daring undertaking, even for experienced Romans. They were not able to fully calculate the forces that the arched bridge would have to withstand. The arches span 15 to 24 meters in the lower level, constructed at a time where the average span would have been four to five meters. The bridge is an incredible for the time 50 meters high (161 ft.) and 274 meters (899 ft) long. We are still in awe of the architecture, especially if you consider that it is thought Roman general Marcus Vipsanius Agrippa ordered it to be built around the year 19 BC, making the Pont du Gard 2,000 years old!