Much of Lebanon is made up of karstic limestone. Some of the most spectacular rock formations occur in the Keserwan area of Mount Lebanon, especially in the areas of Ajeltoun, Rayfoun, Qlaia'at, Ashqout, Faitroun, Hrajel, Wata el-Jouz, Mazra'at Kfar Debian, and areas in between.
The Karst makes life in Lebanon possible. The water, instead of immediately running off, percolates deep into the mountains and comes out as springs. The most famous of these is the one that comes out of Jeita Caverns and supplies Beirut with water year-round.