What's it like?
Many deserts are found in bands along 30 degrees latitude north and 30 degrees latitude south (between the red lineson the map).
Sometimes deserts located by mountains and are caused by the "rainshadow" effect. As air moves up over a mountain range, it gets cold and loses the ability to hold moisture -- so it rains or snows. When the air moves down the other side of the mountain, it gets warmer. Warm air can hold lots of moisture, so it doesn't rain as much, and a desert is formed.
Top 5 largest deserts in the world
1Sahara desertNorthern Africa9.10 million km2
2Arabian desertSouth-west Asia2.33 million km2
3Gobi desertCentral Asia1.29 million km2
4Patagonian desertArgentina / Chile673,000 km2
5Great Basin desertUnited States492,000 km2