Overlooking Lake Natron and the bush land of Kenya to the north, Ol Donyo Lengai, which means ‘the Mountain of God’ in Maasai, is an active volcano and one of Tanzania’s most spectacular and undiscovered climbs. The volcano erupts sporadically, sending small streams of grey lava down the crater rim and spitting hot ash high into the air. The trek to the top of Lengai is very steep and a true challenge which is attempted only by hikers with the good level of fitness.