 The scenery of rocky headlands , ravines , waterfalls and towering cliffs gained the Exmoor coast recognition as a heritage coast in 1991 . With its huge waterfalls and caves , this dramatic coastline has become an adventure playground for both climbers and explorers . The cliffs provide one of the longest and most isolated seacliff traverses in the UK . The South West Coast Path , at 1 @,@ 014 kilometres ( 630 mi ) the longest National Trail in England and Wales , starts at Minehead and runs along all of Exmoor 's coast . There are small harbours at Lynmouth , Porlock Weir and Combe Martin . Once crucial to coastal trade , the harbours are now primarily used for pleasure ; individually owned sailing boats and non @-@ commercial fishing boats are often found in the harbours . The Valley of the Rocks beyond Lynton is a deep dry valley that runs parallel to the nearby sea and is capped on the seaward side by large rocks , and Sexton 's Burrows forms a natural breakwater to the harbour of Watermouth Bay on the coast . 
