The Caucasus run between two seas - the Black Sea in the west and the Caspian Sea in the east. Three countries share the mountain range: Azerbaijan, Georgia and Armenia. From the top of the highest peaks, on a really clear day, you can see all the way across to the other side.
In the high villages of northern Azerbaijan, families live very simply. They keep sheep and cows, grow vegetables in small terraced gardens, and bake bread in clay ovens called 'tendir'. Children in the mountain villages know how to ride a horse and find their way home in the snow.
One of the most famous mountain villages is called Khinalug. It sits 2,300 metres up - higher than most clouds. It is one of the highest villages anywhere in Europe. The people there speak a language all of their own, which only a few thousand people in the world understand. The language has no written-down letters; it is passed on by listening and speaking.
In winter, the mountains are covered in deep snow. There is a ski resort called Shahdag where families come from Baku to learn to ski. In summer, the same slopes are bright green and full of wildflowers. Many wild animals live up there too: brown bears, deer, wild boar, and even the rare Caucasian leopard.