Ever since 1906, a hotel has been run at the site where Hotel Hammersø sits. In 1942, Magnus and Karen Kjær purchased the hotel, and despite the difficult conditions of World War 2, things went well. In 1944, however, German troops confiscated Hotel Hammersø, and the site was used as a field hospital for wounded German soldiers from the East Front. This was a tough time for the otherwise wonderful hotel building, and it was quickly worn down.
Denmark was liberated in May 1945. Unfortunately, the liberation did not apply to Bornholm, which was instead occupied by Russian forces.
The Russian forces immediately confiscated the best-located hotels in Bornholm – including Hotel Hammersø. In the period leading up to 1946, when the Russian troops returned Bornholm to Denmark, Hotel Hammersø served as a command centre for Russian officers.