At Forteiland in IJmuiden — a fort built in 1881 part of the UNESCO Stelling van Amsterdam — event agency PBN runs two escape experiences accessible only by boat ('De Fortwachter'); the crossing is already part of the story. In 'Het Von Braun Mysterie' you unravel mysteries in an authentic German WWII bunker where rocket scientist Von Braun allegedly worked, while 'The Great Escape' is marketed as 'the largest escape room in the Netherlands': you wander for up to four hours through the underground tunnel system of the island. Everything is sold as a premium evening package with guided tour, drinks and a five-course shared dinner in the fort — no hourly puzzle-solving available à la carte. Public reviews of the puzzles themselves are sparse; visitors especially praise the boat crossing, the raw bunkers and dining on the island, with substantial group pricing (roughly €99–170 pp all-in).