BBC Rewind: Plan for self-contained city off Norfolk coast
Archive video from 1968 showed futuristic plans to build a self-contained city 15 miles (24km) out at sea.
The BBC's Tomorrow's World programme announced the development for up to 30,000 people could be built off the coast of Norfolk.
It said high-tech walls and an enclosed lagoon would keep temperatures in "Sea City" mild all year, while helping to ease overcrowding in towns on the mainland.
"The day might come where a chain of cities like this would ring the coast of Britain," it concluded.
