Nuclear power
Enrico Fermi made the first nuclear reactor in the year 1941.  Many reactors were built in the U.S. during World War II during the Manhattan Project.  In 1954 the first nuclear power plant started in Obninsk near Moscow.  Most nuclear power plants in the U.S. were built during the 1960s and 1970s.  Nuclear reactors also power some large military ships and submarines.