The sand dunes of the Tunisian Sahara can reach 30 metres high - about the height of a ten-storey building - and the wind constantly shifts them into new shapes. Travelling over these dunes by camel or 4x4 vehicle is a popular adventure. At night the sky above the desert is astonishing because there are no city lights to block out the stars.
Near the village of Matmata, local Berber people traditionally built their homes underground - carved right into the rock - to stay cool in summer and warm in winter. These remarkable pit-houses are still there today. Filmmakers loved the look of them so much that the village became the planet Tatooine in the original Star Wars films. Visitors can even stay overnight in one of the cave hotels.
The desert is not empty - it is full of life if you know where to look. Fennec foxes, desert hedgehogs, and scorpions hide in the sand. Date palm oases create tiny green islands of shade and water. Camel caravans once crossed the Sahara carrying gold and salt, and today camel trekking is one of the most popular activities for visitors.