Dunes of sand hundreds of miles long streak their surface. With no cloak of vegetation to conceal them strange formations are exposed in the naked rock. Africa's Sahara is the largest desert of all. It's the size of the United States and the biggest source of sand and dust in the entire world. Sandstorms like these appear without warning and reduce visibility for days over areas the size of Britain. Dromedaries, single-humped camels, take these storms in their stride. The heavy sand rises only a few metres above the ground, but the dust can be blown 5,000 metres up into the sky. The ferocious wind, armed with grains of sand, is the agent that shapes all deserts.


大风吹积成的沙丘长达数百公里，横亘在沙漠的表面，没有植被遮掩，它们在裸露的岩石中间，形成奇怪的形状，非洲的撒哈拉沙漠是，世界上最大的沙漠，它的面积几乎与中国的面积相当，在这里经常是狂风大作，像这样沙尘暴会骤然而起，让你在几天时间内，在相当于英国国土面积的范围内，什么也看不见，单峰驼却能在这样的沙尘暴中，行走自如，较大的沙粒只能上升几米，但沙尘则可以被吹拂到5千米的高空所有沙漠的形成，都是通过夹裹着沙尘的狂风。