The Germans were the first to propose nuclear science, and some of their top minds advanced the field in the 1800s and early 1900s. That’s why it’s probably a little surprising that America had the first functioning nuclear reactor. And the first bomb. But the Nazis had not just one nuclear program, but three. And one of the teams had an honest-to-god reactor ready to go. The German nuclear program had two major prongs. There was a weapons program that was begun in 1939, but the shortage of scientists quickly short-circuited the effort. Later that year, a new team was...