Question: What project was a scientific effort led by Germany to develop and produce nuclear weapons during World War II, and was subject to the Norweigian heavy water sabotage to prevent it?
Sentence (from "German nuclear weapon project"): The first effort started in April 1939, just months after the discovery of nuclear fission in December 1938, but ended only months later due to the German invasion of Poland, after many notable physicists were drafted into the "Wehrmacht".
Relevant evidence: No