Dartmoor is an area of high moorland in the centre of Devon. It is to the north of Exeter. Dartmoor is the remains of a huge volcano that erupted several hundred million years ago. When the eruption was over, the magma chamber deep underground began to cool, and the lava in it turned to granite. Then, over the millions of years since, the rocks above were slowly worn away, so that we now see the granite of the magma chamber as the tors of Dartmoor.

The tors are broken rocks on the highest points of the moors. They are broken up into slabs because they were formed deep underground. As they came to the surface, the pressure became less and so the granite began to expand. But granite is a brittle rock, and so what happened was that the rock broke up into pieces. That is what you can see now.

Dartmoor was once home to Stone Age people, at a time when Britain was warmer and drier than it is now. Today it is hard to farm on the moors, and Dartmoor is famous for its sheep and its ponies. Dartmoor is a National Park.