Tucked away in the Kalahari Desert of north-west Botswana, near the border with Namibia, is an enigmatic group of rocky outcrops known as the Tsodilo Hills. It is remarkable not only for its ancient San bushman paintings of wildlife, but also for the natural, sunset hues of its stone, ranging from tangerine to dusky pink to rust, from pale aubergine and icy grey to slate blue. I love pebbles, crystals, semi precious stones, and unusual rock formations, and I went a bit crazy

When people think of the tropical rainforest, I believe the picture most have in their minds is of trees. Lots and lots of tall trees. An immensity of dense vegetation, lush and humid, like an endless field of broccoli when viewed from a plane, or a wall-to-wall carpet of mosses when viewed by a god. (Or people might think of those trees cut down in swathes, to make room for cattle, oil palms, or roads.) But when I think of the rainforest, I think of water. Of streams and riv