Deserts are the driest places on planet Earth. Only a small amount of rain falls in these areas and sometimes it may be even several years before rain lands in the same place! Amazingly more than a third of planet Earth's land surface is covered by desert.

When you think of a desert you probably imagine an endless landscape of sand with great big sand dunes. But not all deserts are sandy. Other deserts may be flat, stony places, or have rugged, rocky hills and mountains, though most are a combination of landscapes.

Most deserts are also really hot during the day and very cold at night because there are no clouds to keep in the heat. These conditions combined with the lack of water makes them very difficult places to live.

But amazingly deserts are home to several different plants and animals that have specially adapted to the difficult dry conditions. A desert can even become quite green for a brief time after a rare downpour of rain, as grass and flower seeds quickly spring up before the desert dries up again.

Other desert plants are specially adapted to absorb and store as much water as possible – like this cactus plant. These plants have very small or even no leaves and thick waterproof skins that help to stop any water from escaping. Other plants have really long roots that can trap water far below the surface.

The animals that live in the desert also have special features that enable them to cope with the hot, dry conditions. Scorpions and wolf-spiders have a really thick outer covering which helps prevent water loss. And most animals like lizards and rats are only active at night when the temperature is cooler.

Although deserts are home to plants and animals, they do not contain the same diversity as other habitats such as forests and woodlands. And unfortunately large areas of land that were once covered in forest are now being turned into deserts because the trees have been cut down and all the valuable soil has been blown or washed away.

WWF has many projects around the world which are helping to prevent forests and woodlands from being cut down. Much of this work involves working with local people to help them find ways of using the forest for their everyday needs without letting them disappear altogether.