JUNE 29, 1955: The first B-52 Stratofortress strategic bomber enters service with the 93rd Bombardment Wing at Castle Air Force Base. Designed as the primary airborne component of America’s strategic nuclear deterrent, the massive bomber had a wingspan of 185 feet and was powered by eight Pratt & Whitney engines, allowing it to carry 35 tons of payload at up to 650 miles per hour. Flown by a five-man crew, the B-52 also excelled at delivering conventional munitions, and it later saw extensive service over Vietnam during Operation Linebacker and on thousands of sorties during Operations Desert Storm and Enduring Freedom. A total of 744 B-52s were built, with the last delivered in 1963, and more than 70 are still in active service today, sharing the air with their more modern bomber descendants, the B-1B Lancer and B-2 Spirit. SLIDESHOW: B-52 Stratofortress