the other engineers recorded their names and the year on "Maxwell's Column", a great limestone pillar some from the entrance. About further on, in the so-called "Pantheon", they wrote their names and details of the expedition on paper, sealed it in a bottle and placed it on top of a stalagmite. The lime-impregnated water has since covered the bottle with a thin white film, permanently fixing it to the stone. Between 1892 and 1940 further expeditions were carried out by English, American and French explorers. Their expeditions brought them to a depth of . Since the 1940s, Lebanese explorers have pushed even deeper into the Jeita grotto. Many of these spelunkers are members of the Speleo Club du Liban (Lebanese Caving Club) founded in 1951 by the first Lebanese speleologist Lionel Ghorra. Their expeditions revealed a great underground system which is now explored to an overall length of nearly . In 1958 the lower caverns were opened to the public, meanwhile exploration was still underway mainly by the Lebanese Caving Club. This exploration led to the discovery of the elevated dry branch of the grotto later referred to as the upper galleries. In 1962, the Spéléo Club contributed to a study of the upper galleries aiming to provide an access tunnel which was to be dug for touristic development purposes. Work on the access tunnel was begun in 1968. Its opening was followed by the installation of a series of walkways which permitted tourists safe access to the upper galleries without disturbing the natural landscape. In 1969, a concert with electronic music by the French composer Francois Bayle was held in the cave to celebrate the inauguration of the upper galleries. This event was organized by the Lebanese artist and sculptor Ghassan Klink. Other cultural events have taken place in this unusual surrounding, including a concert by the world acknowledged German composer Karlheinz Stockhausen in November 1969, and more recently, in 2008 a classical music concert by Lebanese-Armenian composer and pianist Guy Manoukian. The caverns closed to the public due to the Lebanese civil war in 1978; both tunnels leading to the lower and upper galleries were used to store munitions, and the outside buildings for military purposes. The caves reopened in 1995 and remain one of the country's key natural attractions. Archaeology Jeita I (sometimes referred to as Nahr-el-Kelb) is a dry cave, 56 metres deep to the east