The Pont du Gard was built short­ly before the Chris­t­ian era to allow the aque­duct of Nimes (which is almost 50 km long) to cross the Gard riv­er. The Roman archi­tects and hydraulic engi­neers who designed this bridge, which stands almost 50 m high and is on three lev­els — the longest mea­sur­ing 275 m — cre­at­ed a tech­ni­cal as well as an artis­tic mas­ter­piece.