Catalonia´s greatest subterranean lake

Under the city of Tarragona lies a huge (3-kilometre long) cave with enormous halls, labyrinths, clear water and a gallery excavated by man. An extensive and complex subterranean cave and cavern system carved by groundwater that make it the greatest underwater lake in Catalonia. The construction of an underground parking in C/Gasòmetre, 32 in 1996 brought this speleological miracle to light. In pre-Roman times and in republican-era Tarraco, the cave was one of the city´s principal water resources. The discovery of the subterranean lake - some 13 metres below the surface of the old Roman city and with its epicentre below the Colonial Forum - has helped to make more sense of the remnants of Roman-era and medieval public fountains and wells that had been uncovered (and continue to be uncovered) by archeologists in the lower half of the city. Explorations of the cave are still ongoing to find out its full extent and whether there is a connection with galleries that have been discovered and mapped in the vicinity of the imperial public bath complex (along C/Sant Miquel) and of the Chartreuse factory - an old liqueur-producing factory set up in the early 1900s by French Carthusian monks. SIET, the Society of Speleological Investigations of Tarragona offers tours of the cave with officially certified speleologists. Below is a video of one of their expeditions.