Fort Eiland, armored fort in Ijmuiden

As part of the Defence Line of Amsterdam (Stelling van Amsterdam), the coastal fort of IJmuiden was constructed between 1880 and 1887. Five heavy 24 cm coastal guns faced the sea, tasked with protecting the harbor entrance and locks — the vital gateway to Amsterdam. These powerful cannons were manufactured in Germany by Krupp, commissioned by the Dutch army.

The fort spanned multiple levels, extending far underground across the island. Inside were ammunition magazines, a bakery, a kitchen, sleeping quarters, and all the essential facilities to sustain a prolonged stay in isolation.

By the eve of the Second World War, the fort was considered outdated and held little strategic value. To strengthen it, the Dutch army constructed small machine-gun bunkers known as “stekelvarkens” (“porcupines”). The only remaining one can still be seen on the southwestern tip of the island.

After the German occupation, the Wehrmacht recognized the island’s strategic potential and transformed it into a fortified stronghold, known as a Kernwerk. In German fortifications, a Kernwerk — much like a Dutch reduit — served as the last point of defense, where soldiers were expected to fight to the last man.

The Germans built a range of bunkers on the island, including gun casemates for heavy naval artillery, machine-gun positions, and mortar emplacements. One particularly notable structure is the Type 644 bunker, an expensive concrete shelter costing tens of thousands of Reichsmarks, designed to house two machine guns — a controversial luxury compared to the more practical heavy artillery bunkers.

Perhaps the most remarkable bunker on the island is the one equipped with launch mechanisms for depth charges. From here, German soldiers could fire explosive charges into the North Sea Canal to sink any enemy ships that broke through. Reaching this bunker would have been nearly impossible: attackers first had to overcome coastal guns on the piers and locks, and then navigate through nets and cables stretched across the canal.

The depth charge bunker lies directly next to the surviving “stekelvarken” and can be clearly seen from the mainland shore.

The fort and its bunkers are open to visitors through guided tours, offering a fascinating glimpse into this layered history of defense and occupation.