The Cosquer Cave is located in the Calanque de Morgiou in Marseille, France, near Cap Morgiou. The entrance to the cave is located underwater, due to the Holocene sea level rise. The cave contains various prehistoric rock art engravings. Its submarine entrance was discovered in 1985 by Henri Cosquer, a professional diver. The underwater passage leading to the cave was progressively explored until 1990 by cave divers without the divers being aware of the archaeological character of the cave. It is only in the last period (1990-1991) of the progressive underwater explorations that the cave divers emerged in the non-submerged part of the cave. The prehistoric paintings were not immediately discovered by the divers to first emerge from the other side of the sump. The cave was named after Henri Cosquer, when its existence was made public in 1991, after three divers became lost in the cave and died. Description The cave can now be accessed by divers through a long tunnel; the entrance is located below sea level, which has risen since the cave was inhabited. During the glacial periods of the Pleistocene, the shore of the Mediterranean was several kilometers to the south and the sea level up to below the entrance of the cave. Discovery and history Henri Cosquer, a professional diver in Cassis, discovered the drowned entrance to the cave which had been indicated to him by a diver friend in 1985. That same year, he progressively explored the submersed gallery alone and then with a friend and diving instructor from his club until he reached the "stratum" (the part where the gallery narrows and turns 90° to open into the underground lake). Cosquer went back alone once in 1985, discovered the underground lake, but a lamp breakdown forced him to turn back and he was left with a good scare. In June 1990, Cosquer asked for the help of two Belgian cave divers, the brothers Bernard and Marc Van Espen, who had come to dive in Cassis. Following Cosquer's instructions, the two brothers found the entrance of the gallery at -37 metres at the foot of the Pointe de la Voile, near Cap Morgiou. They followed the ascending gallery, swimming slowly and carefully near the ceiling of the gallery to avoid lifting the particles of silt and fine clayey sediments covering the floor in order to not compromise the underwater visibility (to avoid silt out).