World war ii 1940-1946
Bornholm was Danish until World War Two, and then was it taken over by the Germans and later freed by the Russians in 1945; the Russians wouldn't leave Bornholm because of the progressing cold war and only left after being given some special privileges.
History
Bornholm has a long history as a military and political center in the Baltic ocean. The history goes back to the famous Vikings. Numerous findings at southern Bornholm indicate that Bornholm was a well established trading point. Poland, Sweden and Germany are all in the range of 100km. That made Bornholm attractive for the Danish king and the archbishop of Lund and the city of Lübeck during medieval times. Catholics who fasted were only allowed to eat fish and other similar things, so that in the 13th century herring was the main income source on Bornholm.
Early modern
A battle between Denmark and Sweden in 1645 led to Swedish control of the island, but it was brief - they left again the same year. In the Roskildepeace of 1658 Bornholm, Skaane , Halland and Blekinge were given to Sweden. Again the people were forced to pay high taxes to the suppressive forces. The Danish king advised the people of Bornholm to fight back. In 1658 the Swedish commander of Bornholm was killed in Rønne, and the people of Bornholm freed themselves from years of foreign command. Bornholm was given to the Danish king as 'his island'. Jens Kofoed, Poul Anker, Peder Olsen and Villum Clausen became champions of liberty. The same four men have, in modern times, given name to the ferries from Bornholmstrafikken.
Medieval
The European plague struck Bornholm in the middle of the 14th century and halved the population. It was also during this time that Hammershus was constructed, as well as the famous 'round churches'. From 1525 to 1576 Bornholm was in pawn to Lübeck, because the Danish king Frederik I had been supported it in his rebellion against the Swedish King Christian II. The people of Bornholm were suppressed with high taxes and forced work. The people of Bornholm tried to break free but the revolt was fought down in the battle of Ugleenge.
The cold war 1946 - 1989
Bornholm was NATO's Fist towards the east, but a Russian Soviet declaration after World War II stated that the placement of "foreign soldiers" NATO on Bornholm wasn't allowed. So, it was only Danish soldiers who were allowed duty at Bornholm. Because they were able to listen to Soviet, Polish and East German military radio transmissions from a location much further to the east of any other NATO members, enabling military movements and reinforcements deep within the Soviet Union to be monitored, Denmark's contribution to shared NATO intelligence was very highly valued, particularly at times of international tension. More recently NATO radar installations have been placed on the island.
Tourism
Today Bornholm is a popular travel destination for many people in the Baltic region as well as tourists from Sweden, Norway, Germany, Poland and Denmark who are a common sight in the summertime.