Photos

This is a clapper bridge at Postbridge.
I was there on a day with difficult light conditions. The sky was cloudy but somestimes the sun came through and put highlights only on some parts of the landscape as one can make out in this picture.

Some information about clapper bridges from wikipedia.org (have a look at the last paragraph for information about the bridge I show you here):

A clapper bridge is an ancient form of bridge found on the moors of Devon (Dartmoor and Exmoor) and in other upland areas of the United Kingdom including Snowdonia and Anglesey. It is formed by large flat slabs of granite or schist supported on stone piers (across rivers), or resting on the banks of streams. According to the Dartmoor National Park, the word 'clapper' derives from an Anglo-Saxon word, 'cleaca', meaning 'bridging the stepping stones'.

Although often believed to be of prehistoric origin, most were erected in medieval times, and some in later centuries. They are often situated close to a ford where carts could cross.

A fine example is to be found at Postbridge, on Dartmoor. Its slabs are over four metres (13ft) long, two metres (6ft 6in) wide and weigh over eight tons each, making the bridge passable to a small cart. It was first recorded in 1380 and was built to facilitate the transportation of tin by pack horses to the stannary town of Tavistock.