The Saeftinghe nature reserve is a large tidal marsh in the south of the Netherlands close to the Belgian border. The brackish intertidal area is located in the estuary of the Scheldt river where freshwater meets the salt waters of the North Sea. The tidal differences between high and low tide are the biggest in the Netherlands. The reserve offers a breeding area for Redshanks, Bluethroats, Marsh Harriers and many more birds. Saeftinghe was a medieval village, built behind seawalls when land was claimed from the sea. But in the 16th century, the seawalls were breached when the Dutch wanted to prevent the Spanish from reaching Antwerp. The area flooded and the sea reclaimed the land.