At 368 square miles (954 square kilometres), Dartmoor is the largest open space in southern England. It has wild open moorland, granite tors and wooded river valleys. At its edge is a landscape of small fields enclosed by stone walls and hedge banks. Dartmoor has been a stock grazing area for at least 4,000 years and it is, in the main, this kind of farming that has made the Dartmoor landscape worthy of National Park status. The open spaces and sheltered valleys give pleasure to millions of people every year and for the Dartmoor farmers it is their place of work.