Mount Lebanon is limestone, and rain falling on the range disappears into it and comes out lower down through caves, springs and gorges. The results are the country most spectacular natural sites and they are all within a couple of hours of Beirut.
Jeita Grotto
Twenty kilometres north of Beirut, Jeita is a system of two galleries stacked above each other, explored for about nine kilometres. The upper gallery is walked on a boardwalk among formations up to 8 m long, including one of the largest known stalactites. The lower gallery is toured by boat along an underground river which supplies drinking water to much of Beirut. Photography inside is prohibited and cameras and phones are checked at the entrance, which is why almost no images of it exist. The cave closes when water levels rise, usually in late winter.
Baatara gorge
Above Tannourine, meltwater falls 255 m into a sinkhole in the limestone, passing behind three natural rock bridges stacked above one another. The Balaa Pothole, as it is also called, was described by a French speleologist in the 1950s and remains one of the strangest landscapes in the country. The waterfall runs from about March to June with snowmelt and is a dry hole for the rest of the year, so timing matters entirely.
Afqa
At the head of the Nahr Ibrahim valley, a river emerges directly from the mouth of a cave in a 200 m cliff and falls into the gorge. In antiquity this was the source of the Adonis river, said to run red each spring with the blood of the dying god — in fact with iron-rich sediment. The ruins of a Roman temple to Astarte stand beside it and a shrine is still used.
Nahr Ibrahim and Faqra
The Adonis valley below Afqa is one of the best walking areas in Lebanon, terraced and green. At Faqra, at 1500 m, a Roman sanctuary and a natural limestone bridge 38 m across sit in an alpine meadow that is a ski area in winter.
Practicalities
Jeita is open year round except during high water and is easily done as a half day from Beirut, often combined with the Harissa shrine and Byblos. Baatara requires a car and the right season. Roads to all of these are mountain roads and are slower than the distance suggests.
Why the water disappears
The range is built of thick Jurassic and Cretaceous limestone, and rain and snowmelt sink into fissures rather than running off the surface. Water then travels underground for kilometres before re-emerging at the base of a cliff. That is why Lebanon has almost no surface rivers on the western slope above 1000 m and a string of powerful springs below it.