Frequently Asked Questions

The next Bunkerday will be on Saturday 24 May 2025 from 10am to 5pm.

Yes, to visit Bunkerdag you need a ticket. You can buy this at any bunker participating in Bunkerdag.

The ticket takes the form of a wristband. It allows you to visit all the locations. So you only need to buy a ticket once.

During Bunker day, relics such as bunkers and other elements of the Atlantic Wall along the coast of the Netherlands are put in the spotlight and opened to the public for one day. Sometimes the bunkers are still clearly visible and accessible, but sometimes they are overgrown with sand or located on private property. During Bunkerday, we make locations accessible and organise additional educational activities such as guided tours, film screenings and re-enactment.

Bunker day was born in 2014 out of a desire to broaden the scope of the (mostly local) initiatives and activities that exist around Atlantic Wall heritage and to encourage cooperation between these parties. And good luck with that! Bunker day now includes more than 25 organisations, 110 bunkers from the Wadden Islands to the border of Belgium and attracts more than 15,000 visitors annually.

The Stichting Europees Erfgoed Atlantikwall is initiator of the Bunkerdag. It is organised by Donkergroen creators

During the occupation, thousands of large and small bunkers were built at a rapid pace as part of the Atlantic Wall. After the war, these defences quickly fell into disuse, were demolished, shoved under the (dune) sand or otherwise left to their fate. Over time, nature took over “the management” of these bunkers.

Bats and bunkers
Bats in particular discovered the opportunities the bunkers offered to find a frost-free and safe winter home. Because the mostly concrete structures are mostly underground, they are very attractive as mating and wintering places for bats. Male and female bats therefore often ‘meet’ in the bunkers.

Bats are the only flying mammals. Thanks to their special way of life, they can get very old. Ages of more than 30 years are no exception. During the winter period, there is little food to be found for these insectivores. It is therefore vital that they can rely on undisturbed wintering sites. Well-managed bunkers can serve as a safe roost for years.

Of the 20 or so species, it is mainly the water bat, catbird bat, bearded bat and common big-eared bat that use bunkers and corridor systems. It is important for these species that the sites remain undisturbed from early August to mid-May (during the winter and mating periods).

A bunker must meet a number of conditions:

An even climate must prevail inside. That is, the bunker must be frost-free in winter.
It must be humid inside so that the bats do not dry out.
Any predators must not have access.
No disturbance by humans.

The conservation of culturally-historically valuable bunkers goes perfectly together with the preservation and expansion of hibernation sites for bats, amphibians and insects. Want to know more about bats? Then take a look at vleermuis.net and or zwgzh.nl.

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