Defence Line of Amsterdam

The Netherlands has a tradition of using water to fight invading armies. Across the Netherlands there are water defense lines. If the Netherlands got invaded by a foreign power areas got flooded to halt enemy advances. This has given the Netherlands a decisive advantage in several defensive conflicts. Amsterdam is surrounded by a network of historical fortresses and water lines that can be inundated, almost turning Amsterdam into an Island. Although the water lines around Amsterdam have never been used in a war, it did worry the Germans enough not to invade the Netherlands in the first world war. These days the Defence Line of Amsterdam (Stelling van Amsterdam) mostly serves as a UNESCO world heritage site and is open to visitors.