Clapper bridges are unique to the dartmoor area of England. There are 30 bridges in total on Dartmoor, being constructed in the thirteenth and fourteenth centuries by medieval tin workers and farmers as crossings over the many small rivers that traverse the moorland. This clapper bridge straddles the East Dart River, just twenty meters from the main road bridge and is clearly visible as you drive through the village of Postbridge. The bridge is constructed from four large granite slabs supported by three granite piers. The large slabs are each over 4m long and 2m wide and weigh over 8 tons each.