Kroontjesbunker

The FL250, nicknamed the “Kroontjesbunker” (Crown Bunker) because of the distinctive shape of its tower, served as the headquarters of the German anti-aircraft defense for the Verteidigungsbereich Den Helder (Defense Sector Den Helder). It functioned as the command post for the German Navy operating in both Texel and Den Helder. From here, Allied aircraft movements were tracked, logged, and air defense actions coordinated.

A glass plotting wall was used to transmit aircraft positions to anti-aircraft batteries. Data came from radar stations along the coast and from more distant observation posts, such as those in Zandvoort and Terschelling. Together, they formed a chain of observation points capable of following every flight movement in detail. Based on this information, defense plans were drawn up, and coastal gun positions were activated when necessary.

The Kroontjesbunker is one of only two surviving examples of this bunker type in the entire Atlantic Wall, and the only intact one in the Netherlands. Its tower was used as an air observation post for visual detection of aircraft. Surrounding the main bunker lies a complex of shelters, mostly type M151, hidden among the Grafelijkheidsduinen.

The Kroontjesbunker is open to the public on special occasions such as May 4th & 5th (Remembrance and Liberation Day), Bunkerdag, Open Monumentendag, and by appointment.