Deserts generally receive less than 40cm (16in) of rain a year.

Around one third of the Earth's surface is covered in deserts.

The original meaning of the word desert is 'an abandoned place'.

Many of the ice free regions of the Arctic and Antarctic are known as polar deserts.

Only around 20% of the deserts on Earth are covered in sand.

Areas covered in ice or snow can sometimes be called 'cold deserts', compared to 'hot deserts' in warmer areas.

The largest cold desert on Earth is Antarctica.

The largest hot desert on Earth is the Sahara.

The Sahara Desert is located in northern Africa, spanning 12 different countries.

The Arabian Desert in the Middle East is the second largest hot desert on Earth but is substantially smaller than the Sahara.

Other large deserts include the Gobi Desert in Asia, the Kalahari Desert in Africa, the Patagonian Desert in South America, the Great Victoria Desert in Australia, the Syrian Desert in the Middle East and the Great Basin Desert in North America.

The Gobi Desert is located in the north of China and the south of Mongolia. It is growing at a fast rate due to desertification, a process that turns fertile lands into desert areas. It is caused by humans cutting down forests, droughts, climate change and other environmental factors.

Located in South America, the Atacama Desert is the driest place in the world.

Hot deserts usually feature high temperatures in the daytime and cold temperatures at night.

Deserts have very low humidity.

Despite the extreme conditions, deserts are home to a range of well suited plant life including various shrubs and cacti. They are also home to animals such as lizards and coyote.

With lack of water, high daytime temperatures and sometimes freezing conditions at night, deserts can be extremely dangerous places for humans.

Shallow, salty lakes can form temporarily from time to time in deserts.

Deserts often contain large mineral deposits.

Deserts can be good locations to farm solar energy.