TOPEKA, Kan. (WIBW) - While U.S. ground troops battled on the front lines of the Vietnam War, an elite group of the U.S. Navy worked below the surface in the deep waters of the Pacific Ocean. U.S.

Some of the most powerful weapons in history never had to be used. Submarines have quietly reshaped warfare by doing something even more effective than attacking: forcing enemies to hesitate. Hidden ...