Plateau of southwest Devon, England; mostly a national park, 956 sq km/369 sq mi in area. Over half the region is around 300 m/1,000 ft above sea level, making it the highest and largest of the moorland areas in southwest England. The moor is noted for its wild aspect and the tors , rugged blocks of bare granite, which crown its loftier points. The highest are Yes Tor, rising to 619 m/2,030 ft, and High Willhays , which climbs to 621 m/2,039 ft. At Princetown, 11 km/7 mi east of Tavistock, is Dartmoor Prison , a high-security long-term institution. The region provides grazing for sheep, cattle, and Dartmoor ponies , a semi-wild breed probably descended from animals turned out on the moor in the Dark Ages. Dartmoor was the setting for Arthur Conan Doyle's The Hound of the Baskervilles . Physical features The slopes beneath the granite tors are covered by gorse and heather, and the low-lying areas are characterized by broad tracts of dark peat and bog with bright green grass. The region…