How Hitler tried to terrorize the seas with U-boats during World War II

"The only thing that ever really frightened me during the war was the U-boat peril," British Prime Minister Winston Churchill reportedly said reflecting on the Second World War.

By the end of the war, Hitler's Kriegsmarine, the navy of Nazi Germany, built 1,162 U-boats, which is short for the German word "Unterseeboot," or undersea boat.

In the fall 2015 issue of Weapons of World War II magazine, Marc DeSantis explains how the U-boats were used during World War II.