Lake Turkana is the largest lake in Kenya and runs south from the Ethiopian border for about 250kms, in a long narrow body of water, never more than 50 kms wide. There are three major volcanic islands, North, South and Central Islands, set in a string down the middle of the lake. The water is slightly alkaline, and lake Turkana's green waters - sometimes referred to as the 'Jade sea' - make a bright contrast to the desolate countryside. Located in the far north of Kenya, the surrounding country is harsh desert, rocky and dusty. To the south of the lake lies Teleki Volcano, and to the east, Kulal mountain, which is topped with cedar forests, and from which the notorious winds blow across the lake. The lake is home to the largest population of Nile crocodile in the world, about 20,000, and there are Nile perch, tiger fish and some tilapia. There is a profusion of birdlife, including many migrants. On the eastern side of the lake lies Sibiloi National Park, where you can see the fossilised forest, and visit the prehistoric site at Koobi Fora.