Holland's Floating Houses

"Holland is Europe's most densely occupied country, and two-thirds of the Dutch live below sea level. If there are to be more houses, more land will have to be created for them, or they will have to be built beside water. The country has been creating artificial land, or polder, for centuries. There are minor floods here every two or three years... The hollow concrete pontoons that serve as foundations will be able to rise, guided up a pair of 15ft concrete piles, when the flood waters come. The clapboard superstructure, meanwhile, is light and boat-like. Flexible pipes and ducts are designed to ensure that water, gas and electricity supplies, and sewage disposal function even when the houses rise a whole storey. Boats can be moored alongside..."