Did you know that parts of the Netherlands are lower than the sea? Nowadays many people live in places where fish used to swim. The Dutch made a lot of their land themselves by draining lakes. Most of this new land is polders. The Netherlands is famous for its polders, which make up two-fifths of the country.

A polder is a piece of land that is lower than the sea and is protected from the water by dikes. Large pumps keep the polders dry. Without dikes and pumps, many parts of the Netherlands would disappear under water again.

For centuries, the Dutch have had to fight the sea and the rivers. Even today it is hard work to keep the Netherlands dry and stop the sea taking back the land. So the Dutch are experts at building dikes, dams and everything that goes with them.

The lowest areas of the Netherlands, which are actually the delta of the Rhine, Maas and Waal rivers, have often been flooded. In 1953, heavy winds and high tides burst the dikes in the province of Zeeland. The islands in the province were flooded.

After that, a series of enormous dams and flood barriers was built to protect the islands. It was the largest project of its kind anywhere in the world and took 30 years to build. It is known as the Delta Project.