arch architecture bridge Crickhowell current flow Great Britain historical old Powys river stone united kingdom Usk wales water welsh background battlements black cobblestones fortifications historic history house medieval middle age postcard rampart town village canal choked decay desuetude disrepair disuse England english reeds rural towpath trees wiltshire blue britain british classic closeup construction decorative detail landmark London roofs sky steel tower towers church thames cables California Golden Gate monolith ocean red rivets rusted San Francisco structure symbol tall Alcantara ancient secure security Spain spanish Toledo Cornish cornwall pillar railway transport viaduct