At first glance, they look like a couple of giant inflatable garden chairs that have washed out to sea. But they are, apparently, the ultimate solution to rapidly rising sea levels.
This computer-generated image shows two floating cities, each with enough room for 50,000 inhabitants.
Based on the design of a lilypad, they could be used as a permanent refuge for those whose homes have been covered in water. Major cities including London, New York and Tokyo are seen as being at huge risk from oceans which could rise by as much as 3ft by the end of this century.