History of Mach 1: 73 Years Ago — Yeager Breaks the Sound Barrier

On June 10, 1948, The U.S. Air Force confirmed that Capt. Chuck Yeager had repeatedly attained supersonic speeds in the Bell X-1.
Background
But it was on October 14, 1947, that Chuck Yeager, now 97 and a Brigadier General (retired), actually broke the sound barrier for the first time.