Lesotho is the only country in the world that lies entirely above an altitude of 1000m, earning its name "the mountain kingdom". The Lesotho lowlands would be highlands anywhere else, and are made of sandstone . Right across the country, at about 1400m, the sandstone gives way to basalt , a dark grey rock thrown up by volcanic eruptions several million years ago. Roughly marking the beginning of the Lesotho Highlands, basalt is a hard rock that resists erosion, unlike the sandstone, which has been carved by the wind over the millennia into an infinite variety of shapes that have turned the hills into the kingdom's natural sculptures.