On a small rise in a field northeast of Knivholt Skov, close to Knivholtvej, stands a modest concrete structure that many locals casually refer to as a “bunker.” At first glance, its material and age make that assumption understandable. Yet despite appearances, this structure was not built by German forces during the occupation of Denmark, nor was it intended for military defense. Its origins are instead tied to the immediate aftermath of the Second World War.
When the German occupation ended in May 1945, Denmark was left with a large humanitarian challenge. In the final months of the war, the German authorities had transported tens of thousands of civilians—primarily women, children, and elderly people—from areas such as East Prussia to Denmark. These refugees were dispersed across the country and housed wherever space could be found, including schools, community halls, and former military facilities.
After the German withdrawal, responsibility for these refugees fell to the Danish authorities. At first, even the total number was unclear. By mid-May 1945, the Ministry of the Interior estimated that around 250,000 German refugees were in Denmark. Beyond providing food and medical care—critical tasks due to widespread illness and high mortality—there was an urgent need to consolidate the refugees into larger camps so that occupied buildings could be returned to civilian use.
In northern Jutland, and especially around Frederikshavn, several such camps were established. Existing German barracks at Kragholm and Røntved were repurposed, and in 1946 a third camp, Knivholt Camp, was built near Knivholt Forest using prefabricated barracks purchased from Sweden. At its peak, Frederikshavn housed more than 11,000 German refugees, with Knivholt Camp alone accommodating between 4,000 and 6,000 people. It became the last refugee camp in the area and remained in use until its closure in March 1948.
One of the practical challenges of operating Knivholt Camp was wastewater management. In nearby Røntved Camp, sewage had been discharged directly into the surrounding landscape, causing dissatisfaction among local residents. For Knivholt Camp, authorities decided to route wastewater toward Lerbækken, a small stream in the area, but also attempted partial treatment beforehand. As a result, in 1946 they constructed the concrete structure that still stands today. It functioned as part of a simple wastewater treatment facility, located roughly halfway between the camp and the stream, near what is now the junction of Knivholtvej and Vendsysselvej.
Once the camp was closed, the facility quickly became obsolete. It was never dismantled, however, and remained in the landscape. In 1951 there were discussions about reusing it in connection with new sewer infrastructure in the Øster Flade area, but these plans were never realized.
Similar facilities were built elsewhere in Denmark during the same period. For example, a comparable wastewater installation was constructed near Kragskovhede State Prison, which in 1946 housed Danish collaborators convicted of treason. That structure still exists, hidden in woodland east of the prison, where wastewater was discharged into Kragskov Å.
Today, the concrete structure near Knivholtvej is a quiet reminder of a lesser-known chapter of post-war history—one rooted not in combat, but in displacement, logistics, and the challenges of managing the aftermath of a global conflict.