the same year, culminating in Villum Clausen's shooting of the Swedish commander Johan Printzensköld on 8 December 1658. Following the revolt, a deputation of islanders presented the island as a gift to King Frederick III on the condition that the island would never be ceded again. This status was confirmed in the Treaty of Copenhagen in 1660.
Swedes, notably from Småland and Skåne, immigrated to the island during the 19th century, seeking work and better conditions. Most of the migrants did not remain.
Bornholm, as a part of Denmark, was captured by Germany relatively early in the Second World War, and served as a lookout post and listening station during the war, as it was a part of the Eastern Front. The island's perfect central position in the Baltic Sea meant that it was an important "natural fortress" between Germany and Sweden, effectively keeping submarines and destroyers away from Nazi-occupied waters. Several concrete coastal installations were built during the war, and several coastal batteries had tremendous range. However, none of them were ever used, and only a single test shot was fired during the occupation. These remnants of Nazi rule have since fallen into disrepair and are mostly regarded today as historical curiosities. Many tourists visit the ruins each year, however, providing supplemental income to the tourist industry.
On 22 August 1943 a V-1 flying bomb (numbered V83, probably launched from a Heinkel He 111) crashed on Bornholm during a test – the warhead was a dummy made of concrete. This was photographed or sketched by the Danish Naval Officer-in-Charge on Bornholm, Lieutenant Commander Hasager Christiansen. This was the first sign British Intelligence saw of Germany's aspirations to develop flying bombs and rockets which were to become known as V-1 and V-2.
Nazi Atomic Bomb development on Bornholm
On 14 October 1945, Professor Paul Rivet disclosed to journalists in Paris that the Nazis had
