Fanø Atlantic Wall Bunker

The bunkers on Fanø were built using the so-called standard construction system. For each type of bunker there was a kit with drawings and formwork boards, which allowed mass production with a uniform standard. The walls were between 2 and 3.5 m thick and consisted of up to 1,500 m³ of reinforced concrete. The cost of building a bunker would be around €500,000 today. Although Fanø is made of sand, this was unsuitable for bunker construction because the sand from Fanø is too fine-grained and round to bind sufficiently. The sand therefore had to be procured from the mainland.On Fanø, around 75,000 m² of concrete were used for the bunkers under the most adverse conditions, which corresponds to almost 11,000 truckloads or the amount of concrete required for a two-lane motorway 75 km long (Hamburg to Lübeck).
(Source: fanoe-ferienhaus.com/gehenswuerdigkeiten/bunker)

Many of the bunkers on Fanø can be explored without equipment.