Once the foundation for the forum, the cryptoporticus in the French city of Arles dates back to the 1st century BC. Its origins are most likely Greek, as indicated from mason’s marks, and it is thought to have been used as slave barracks. It is currently underneath the Chapel of the Jesuit College and the City Hall.

A cryptoporticus is a semi-subterranean gallery that supports an aboveground portico (a porch-like structure). This particular cryptoporticous consists of a horseshoe containing three galleries that are separated by pillars intended to support the structures above. 90m long and 60m wide, several ancient sculptures were found during excavation, and they currently reside in Musée de l’Arles Antique.

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

Adapted with permission from Exploguide.com dedicated to travelers looking for alternative and off-the-beaten-track travel.