The Germans manufactured the u-boats.
The submarines attacked Pearl Harbor
It sank up to 2,779 ships in world war 2
The Germans then threatened to use only Uboats for war and blew up a few ships.
the buiding of copper mill was built during world war 2
It wasn't built during a war, it was after World War II.
6,495
It was built during the second world war in 1934.
If there were U-boats in the Black Sea they could have traveled throug the Mediterranean Sea, the Aegean Sea, the Sea of Marmara, the Hellespont, and the Bosphorus into the Black Sea.
Much of the East coast was blacked out as Nazi Uboats were sinking shipping all the way from NY to FL. They also did some shelling with their small deck guns.
because of the alliances the US had made previous to the start of the war along with the threat of the German Uboats attacking US civilians and property.
It was built in 1961 during the Cold War.
Thessaloniki, or Salonika.