The Cryptoportique, Roman vestiges, Arles

Arles was during Rome time a very important city. Its forum, located on a slope, had to be stabilized by underground tunnels, forming what is called a cryptoportique (cryptoporticus): thus, the southern gallery is dug into the rock, while to the northern one was backfilled with several meters of stones.

Only the northern gallery, because of the slope, was opened on the outside (which is now the current site of the Forum square).

It is estimated that this complex was built shortly after the founding of Arles, during the late first century BC.

The site has been declared an historic monument in 1841 and a World Heritage by UNESCO in 1981.