A village of bunkers was built on Schiermonnikoog as part of the Atlantic Wall: Schlei. The island residents called the fortification Schleidorp (Schlei village). Construction lasted about eighteen months. In addition to bunkers, the 'village' also consisted of radar installations, barracks and anti-aircraft artillery. Schlei was part of the coastal surveillance system. The Seeburg bunker was the central post and was connected to all the surveillance systems on the island. This bunker, now Bunker Museum Schlei, is certainly worth a visit.
All traces of the anti-aircraft battery have been lost. Only the foundations are still visible, and several bunkers lie hidden under the sand. Bunkers are still visible at the Schlei fortification and one of them houses a Bunker Museum. Here you can see how data were projected on the ‘Seeburgtisch’, a glass plate with the contours of the Dutch coast, during the war. Small projectors underneath were used to show the positions of both enemy and own aircraft.
The Wassermann bunker is situated at the highest point, slightly land inwards, along the Prins Bernhardweg that leads to the Bunker Museum. The Wassermann bunker is free to visit and offers a beautiful view of the area form the roof.