background Birling Gap chalk cliff coast cracked cream England english evening flints Great Britain natural nature rock stone Sussex texture white Apulia aquamarine arch coastline danger eroded erosion Gargano hole Italy Puglia ripples sea shore water waves crack edge Seaford top bay crumble crumbling dangerous face hazard hazardous high landscape sheer south summer height rockfall Ballard Down blue boat Dorset horizon Old Harry Rocks sky coastal and oceanic landforms Natural landscape ocean Seaford Head bench leisure relax rest seat wooden beach gravel groyne kent shingle St Margaret's Bay view