The Seven Sisters are a group of chalk sea cliffs along the English Channel coast, part of the eroded section of the South Downs hills in East Sussex, south-east England. These cliffs stretch from the mouth of the River Cuckmere near Seaford to the chalk headland of Beachy Head near Eastbourne. The dips, or swales, between each of the seven crests are remnants of dry valleys in the chalky South Downs, which are slowly being worn away by the sea.