Countdown to Atomgeddon — James Howell

The German submarine U-234 left Norway on April 14, 1945, on its last mission to Japan with a cargo of uranium and other strategic military supplies. The cargo included a complete jet aircraft and several tons of documents and plans to build jet aircraft and other German aircraft in a plant to be built in Japan.
Japan and Germany had cooperated in their efforts to build the first atomic bomb by sharing precious raw materials and technology. The Allies had effectively blocked thousands of tons of seagoing strategic military supplies, and later in the war, Germany had invaded the previously neutral country of Russia, cutting off the other route for supplies traffic via the Trans-Siberian Railway.
At the time, there were no aircraft capable of large shipments of cargo over such distances, and the only option was shipping by the only route left: underwater by submarine. The U-234 was the last resort to ship large quantities of cargo over long distances. Aboard the submarine were forty-five crewmen, a German general, three German officers, and two high-ranking Japanese naval officers.
On 8 May, 1945, the submarine was ordered to surrender to the Allies as it plied the cold waters of the North Atlantic. The war had ended in Germany, and the submarine surrendered to the USS Sutton. The surrender of the submarine and its cargo was accomplished with the aid of the Alsos Missions as part of the Manhattan Project. The Alsos Missions continued work in the Pacific to assist the Allies develop and eventually deploy the first atomic bomb.