Cuckmere Haven beaches and cliffs. Aerial footage of beaches and cliffs on the coast by the estuary of the River Cuckmere (Cuckmere Haven). At left are some of the river estuary backwaters and channels. The limestone and chalk cliffs are examples of sedimentary rock formations laid down in ancient oceans and uplifted and eroded to form part of today's coastline. Filmed in Cuckmere Haven, East Sussex, UK.