U-Boot Stützpunkt Drontheim

Trondheim, in the middle of Norway, was the largest German naval base in Northern Europe and was operating from June 1940 until liberation in May 1945. Here, the Kriegsmarine's 13th U-boat flotilla had its headquarters.

The Germans built two U-boat bunkers, Dora I and Dora II, but only Dora I had been completed by the end of the war. Construction of Dora I started in 1941, and when it was finished 2 years later, it measured 502 x 344 feet, and the 5 pens had space for 16 U-boats. The walls were 10 feet thick and the roof comprised 9.8 feet of reinforced concrete.

Dora II measured 550 x 335 feet, and was constructed with 4 U-boat pens.

After the war, Dora I was expanded to 2 floors and is today used as a warehouse and a bowling alley.

Dora II was so badly damaged by Allied bombing that after the war, half of the roof was demolished.

The Germans named their bases by location and the town name “Trondheim” in German is Drontheim. "D" in the German phonetic alphabet is Dora.