Wheal Betsy is an old Engine House just beside the A386 between Okehampton and Tavistock just outside Mary Tavy. The grid reference is SX 510813.
In the 17, 18 and 1900 this area was very important as a mining centre. The mines yielded tin, lead, zinc and silver. Full details can be found on the Legendary Dartmoor site.
Wheal Bestsy is also well known for its leaning tower. The site is in an exposed position so received strong gusts of wind and rain, over the years the National Trust have had to re point the tower and stabilise the walls to ensure it doesn't fall down.
Wheal Betsy is also important as it is the last standing Engine House on Dartmoor. In 1954 the Army was given permission to demolish it but luckily it was saved by the intervention of A.K. Hamilton Jenkin and other campaigners and given to the National Trust.