I've been to the Year 3000,
Not much has changed but they lived under water,
Master of the understatement, neighbour Peter argues that the fourth millennium is pretty much the same as the third, apart from the fact that the entire world is now under the sea.
Living under water could well be a possibility in the future if the Earths ice caps melt, plunging many countries under water. This formed the basis for the Kevin Costner film Waterworld: