I am passionate about climbing and about volcanoes, so I met my match when I first climbed Oldonyo Lengai in 1999. Lengai towers above Lake Natron near Tanzania’s border with Kenya in the bottom of the Great Rift Valley. “Engai’ is the Maasai God, and the mountain literally is translated in Kimaa (the language of the Maasai) as ‘The Mountain of God’. Climbing this stratovalcano is a pretty serious alpine-style scramble…over 2,000 meters of ascent at an unrelenting steep and slippery 45 degrees. It’s the world’s only natrocarbonatite volcano, spewing ‘cool’ lava (which is about 650 degrees celsius, compared to normal (red) lava which is about 1100 to 1200 degrees C). Lengai’s lava appears black and oily, and flows like water. It’s been discovered that it flows ‘quicker’ than water and has the lowest viscosity of any earthly liquid. It’s bizarre stuff, and once it cools and is exposed to water (rain), it turns white. Then if that wasn’t enough, every 40 odd years it violently explodes huge ash clouds and projectile ‘bombs’ (sort of like it’s ‘clearing its nose’). The last such eruptions occurred from Aug’07 to Mar’08, spilling huge amounts of ash all around the mountain. During that time I climbed Lengai about seven or eight times on various routes, partly because of my keen interest but also to collect ash samples for one of Lengai’s leading vulcanologists. During one of my escapades in December of 2007, while sleeping (tentatively) at the edge of the inactive south crater, the mountain had a major eruption. I was sleeping with my boots on in preparation of a quick descent, but instead was treated to a truly awesome display of nature. The ground shook as ash spewed from the crater a few hundred meters away. The ash cloud was generating its own electrical charge, which it would discharge with incredible coloured lightning and crashing thunder. I had never felt so small and insignificant! The crater left behind once these violent eruptions ended in April 2008 was massive; about 400 meters in diameter and 200 meters deep. Experts say it should take 20-30 years for this crater to fill up again with natrocarbonatite lava and the process repeats. Until then we can only gape down from the crater rim below to see the hissing gas vents and cool black lava flowing over the crater floor.