Courtesy of the U.S. Navy
Regarded as the father of the U.S. Navy's nuclear submarine program, Hyman George Rickover was a four-star admiral who helped develop the USS Nautilus in 1954. He went on to direct the building and operations of the American nuclear fleet, which included submarines, aircraft carriers, and cruisers. Rickover gained fame as the longest-serving active-duty military officer in U.S. history, with 63 years of continuous service under thirteen presidents. His achievements twice won him the Congressional Gold Medal for exceptional public service. In 1980, Jimmy Carter presented him the Presidential Medal of Freedom for his contributions to world peace.