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Written by: Taher Nassrulla on 30 September 2015

Ol Donyo Lengai – The Holy Mountain

Ol doinyo Lengai

To the nomadic tribe of the Maasai, there is no other mountain that demands more respect, than Ol Donyo Lengai – ‘the mountain of God’. Located on the base of the east African rift valley in northern Tanzania, Lengai (2960m) overlooks the beautiful Lake Natron.


Ol Donyo Lengai is a strato-volcano and the only active volcano in Tanzania. The last major eruption started in July 2007 and continued on and off until August 2008. Since then the mountain has not had any severe eruptions, just small ones up to 2013.
Lengai is a very unique mountain; it produces natrocarbonatite lava that is not found in any other volcano anywhere else in the world. The temperature of the lava is also quite unique.  At 510°C it is one of the coolest lavas ever recorded. The lava runs quite fast, unlike normal basaltic lava and it can only be seen glowing at night. During the day, Lengai’s lava flows are black in colour almost resembling an oil spill. The colour of the lava can change very quickly from black to grey and then finally to snow white when the lava is exposed to water.


The crater’s appearance changes over time due to small eruptions as well as erosion caused by rain and wind.

The mountain can be climbed; however, it is known to be a very strenuous trek up. When starting at around 22:00-23:00, the summit is reached at sunrise. Once at the top, climbers are rewarded with a breathtaking view of the Great Rift Valley below. The way down can be quite demanding due the steep terrain but it surely is an adventure that will keep your heart beating faster.

I was lucky enough to fly past Oldonyo Lengai in February 2008 when the mountain was in full eruption. The ash plume went up high into the sky up to 2000m and it was a once in a lifetime experience.


For me it was the first time to see a volcanic eruption and I was left in awe.

Author: Taher Nassrulla

Born in East Africa, Taher was intrigued by the natural and geographical diversity of the African bush from a young age. After spending some time in Europe, he returned to Tanzania in 2004 to start a new chapter in his life. Since then he has been spending as much time as possible in the bush, learning. Taher speaks English, Kiswahili and German fluently and is a passionate photographer. Using the skills he has learnt over the years, he now takes tourists out on safari as a German-speaking tour leader and guide.

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