DORA 1

Dora I (Dora 1) is a former German submarine base and submarine pen or bunker built in Trondheim, Norway. Construction of the bunker (designated by the Germans as DORA I) was undertaken during the Second World War. Nearby is the uncompleted Dora II (Dora 2). Trondheim was traditionally referred to as Drontheim in German, and the name DORA is the letter "D" in the German phonetic alphabet.

Following the occupation of Norway in 1940, it was soon realised that the country only had limited facilities for minor naval repairs. More extensive work usually meant a return to Germany. The capitulation of France two months later overshadowed the strategic importance of Norway to some extent, but it was still regarded as a better location for access to the Atlantic and Arctic Oceans than Germany. Nevertheless, better protection for U-boats from aerial attack was required so a bunker-building programme was instigated.

German U-boat bases in occupied Norway operated between 1940 and 1945, when the Kriegsmarine (German navy), converted several naval bases in Norway into submarine bases. Trondheim was an important U-boat base in Norway during the war. It was the home of the 13th U-boat Flotilla and it had 55 U-boats assigned to the flotilla during its service.

The OT used slave labour extensively; five Serbian workers died when a wall fell on them. This incident fuelled a widespread rumor that the Germans simply left the bodies inside the wall. While German engineers did calculate that the five bodies would not weaken the fortification considerably, the bodies were removed before construction continued.

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