Bir Ben Osman is located about two kilometres from the jewel of the Hammam Debagh tourist site and about 22 km from the chief town of the Province of Guelma. It is an underground lake formed by a geological movement in 1878 following an earthquake. Its dimensions are about 100 metres long, 40 metres wide and 15 metres deep. Tourists enter through a small opening in the rocks surrounding the mouth of the lake, and can walk or swim around in boats.
