Denmark, officially the Kingdom of Denmark, is a Nordic country in Northern Europe. The Kingdom of Denmark officially comprises Denmark and two autonomous constituent countries in the North Atlantic Ocean, the Faroe Islands and Greenland.
Denmark was occupied by Nazi Germany during World War II, a situation seized by HYDRA to control one of the islands in the Danish Straits and the castle upon it. Johann Schmidt studied a Viking Runestone found on the island and other relics during his time in the castle.
Captain America and the Howling Commandos
Steve Rogers witnessed a map showing the location of HYDRA facilities in Europe while liberating the prisoners in the Austrian HYDRA Weapons Facility. For that he was tasked to destroy all those facilities with a team while MI6 focused on locating the central HYDRA Headquarters.
On April 7, 1944, Captain America parachuted over an island in the Nazi-occupied Danish straits from a plane, fighting hordes of HYDRA soldiers since before touching the ground. While fighting those first waves he remembered a promise he did to this mother years before, and his friend Bucky Barnes' first lessons of self-defense. Captain America easily defeated the soldiers outside the facility, until he came across a soldier wearing a HYDRA Exo-skeleton.
Within the facility, Johann Schmidt and Arnim Zola discussed the similarities between Captain America and Schmidt now that he became the Red Skull, and Schmidt started to play a record of one of Richard Wagner's operas that inspired his early theories about the truth behind Norse mythology.
The Exo-skeleton proved to be a formidable foe for Rogers, fighting it while Schmidt started speaking through the loudspeakers within the facility about considering himself more than mortal, having heard the call of the gods. Being able to resist the strikes of the Exo-skeleton but not to defeat it, Captain America received the unwitting help of a HYDRA Mini Tank, that failed a shot aimed to Rogers and hit the Exo-skeleton.
Rogers went to save the pilot of the Exo-skeleton from being crushed under the vehicle, receiving a direct shoot from the HYDRA Cannon mounted in the vehicle. This act made Schmidt tell Rogers that he was not the superior man the gods would want to hear their call, as he was mistaking overprotecting the weak with altruism.
While stunned by the shot that made him go through a wall, Captain America was contacted by Howard Stark to guide him in disabling the vehicle still attacking him. Rogers managed to enter the vehicle, finding it was remotely operated by Arnim Zola, and disabling the control box. Zola informed Schmidt that he lost control of the vehicle, confirming Schmidt's opinion that man itself should become the greatest weapon, in order to avoid being wielded by the enemy.
Captain America hijacked the controls of the vehicle, and used it to advance through the facility and attack the HYDRA soldiers within until he reach a stairway he couldn't cross with the vehicle. The timely arrival of the Howling Commandos thwarted an ambush over Captain America, and they went to join Rogers in confronting Red Skull.
Captain America launched himself to attack Red Skull, finding the image he saw was not Red Skull. It was actually a "sonogram", an image formed by sound waves, that allowed him to appear before them from another location, as he claimed his duties at HYDRA prevented him to attend Rogers personally.
Schmidt sent an electrical surge through the batteries of the room, as he had finished studying the location and the artifacts found there, including a viking Runestone. Schmidt offered Rogers a chance to survive, the ensuing explosion would destroy the facility and everyone inside, but Captain America's enhanced speed would allow him to escape. He could decide to flee alone and embrace his superiority letting the "inferiors" die, or perish with them.
Rogers prompted Dum Dum Dugan to take the Howling Commandos and escape, while Rogers would stay behind and save everyone, proving that Schmidt was mistaken. Rogers attacked the Runestone with his shield, delaying the explosion, and buying enough time to let his unit escape.
Having successfully accomplished their mission of destroying the facility, Dugan asked Rogers if the story about the Runestone being a Scandinavian artifact made any sense for him, as maybe the Strategic Scientific Reserve gave him any intel about the plans Schmidt prepared for HYDRA. Rogers answered that was their mission, to find out what Schmidt had planned and to make sure he failed.
End of the War
By April 1945, the Nazi forces were suffering defeats on almost all battlefields of Europe. Around the time of Adolf Hitler's death, the German occupation troops were retreating from Denmark with all speed. On V-E Day, some SS troops in Denmark still refused to surrender.