This is a splendid example of the force of water in action. The place is Crackington Haven in Cornwall, where a very small river runs down a steep valley and into a pool near the beach. The water in the pool seeps through a bank of sand and pebbles, and trickles out onto gently sloping sand which stretches seawards several hundred yards when the tide is out. It faces west so low tide on a sunny evening is the essence of holiday. In October 2010, after some steady rain, the pool filled and burst through the pebble bank. On the first night it cut a channel about two feet deep through the top of the beach. By the next day it was three feet.