Devil's Dyke, Sussex

Devil's Dyke is a dry valley on the South Downs in West Sussex, England, about 5 miles northwest of Brighton, cut roughly 100 metres deep into chalk of Cretaceous age. Despite a local legend crediting it to glacial action, the valley was actually shaped by solifluction: during the last Ice Age permafrost kept the chalk frozen, and summer meltwater saturated the topsoil so that waterlogged material slid downhill and exposed the rock beneath, with rivers completing the valley once the ice age ended. Its surrounding hills rise to 217 metres and give views across the South Downs and the Weald, and on clear days as far as the Isle of Wight. The site holds the remains of an Iron Age hillfort and is now managed by the National Trust as a popular spot for walking, model aircraft flying and hang gliding, with the South Downs Way running through it. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/