My friend Peter recently returned from Tanzania where he climbed Mt Kilimanjaro, the tallest free-standing mountain rise in the world. Kilimanjaro is in fact a giant volcano, but not currently active. Its highest point is Uhuru Peak on the volcano Kibo, which stands at 5,895 metres above sea level (that's 19,340 ft for the metrically challenged amongst you). As the highest point in Africa, Uhuru Peak is one of the Seven Summits.
Obviously I think Peter's mad, but he claims he had a brilliant time, despite the physical challenge - to get to the top you need to trek through the rainforest, then hike through lava-covered plateaus and finally climb the snow-covered slopes to the top. The higher up you go, the more difficult it gets, not just because of the snow, but also because of the lack of oxygen in the air. Still, it's not called the roof of Africa for nothing, and I can only imagine how invigorating it must have been to reach the top and stand next to that sign.
Peter is a keen photographer and took scores of pictures while he was there, all very unusual and impressive. Here are some of the ones I like best.