The Jeita Grotto is a system of two separate, but interconnected, karstic limestone caves spanning an overall length of nearly 9 kilometres (5.6 mi). The caves are situated in the Nahr al-Kalb valley within the locality of Jeita, 18 kilometres (11 mi) north of the Lebanese capital Beirut. Though inhabited in prehistoric times, the lower cave was not rediscovered until 1836 by Reverend William Thomson; it can only be visited by boat since it channels an underground river that provides fresh drinking water to more than a million Lebanese. In 1958, Lebanese speleologists discovered the upper galleries 60 metres (200 ft) above the lower cave which have been accommodated with an access tunnel and a series of walkways to enable tourists safe access without disturbing the natural landscape. The upper galleries house the world's largest stalactite.
The Jeita cave is situated at the center of the western flanks of the Lebanon mountains, more specifically in the Nahr al-Kalb valley, its natural entrance is about 100 metres (330 ft) above sea level. It's located 5 kilometres (3.1 mi) east of the Mediterranean coastline and 18 kilometres (11 mi) north of Beirut within the confines of the municipality of Jeita, in the caza of Keserwan. Jeita I (sometimes referred to as Nahr-el-Kelb) is a dry cave, 56 metres deep to the east of the source cave from where the river flows and connected to it by narrow channels. Jeita II (Dahr el-Mghara) is a rock shelter situated on a platform, above and equidistant between the dry cave of Jeita I and the entrance to the grotto at Jeita III. Jeita III (The Caverns) was a deposit of brown soil that fell from a location suggested to be at the east end of Jeita II, just inside the entrance to the grotto where the tourists are conducted by boat. Jeita IV (Mugharet-el-Mal) is a rock shelter in the cliff upstream from the grotto. It once contained a large quantity of Paleolithic material which has been looted and was deemed unfit for excavation by Sami Karkaby, Director of the Caverns in 1965.