A desert is a region that gets very little rain each year, making it hard for many plants to grow there. Not all deserts are sandy, as some imagine — some are rocky, and some are even very cold and covered in ice.
The largest hot desert in the world is the «Sahara» in North Africa, stretching across several Arab and African countries. Another famous one is the «Empty Quarter» (Rub' al Khali) in the Arabian Peninsula, one of the largest continuous sand areas on Earth.
Deserts are known for extreme heat by day and cold at night, because sand doesn't hold heat the way damp soil does. Even so, animals that have adapted to these harsh conditions live there, like the camel, which can go days without water.
