In 1961, Dyess Air Force Base near Abilene, Texas, became one of six United States Air Force bases selected to host the Atlas F Intercontinental Ballistic Missile system and the only one in Texas. Twelve launch sites with control centers and silos were built in a pattern encircling Abilene, creating a major construction project that strengthened military defense during the Cold War and established the base’s legacy in Texas and U.S. history. The silos housed and protected the Atlas F, America’s first operational ICBM, from all but a direct nuclear strike. Underground hardline communications pits, about 6 feet deep, contained cables and tunnels linking the 12 silos to one another and to the control center at Dyess Air Force Base. Protecting the missiles, their underground launch complexes, and the communications network from physical and electronic attack was known as hardening, and the hardline network was shielded from electromagnetic pulse that could result from a Soviet nuclear attack, since failure to harden could allow EMP to disable all electronics at the sites. The 12 silos formed a 35-mile radius around Dyess Air Force Base, and each silo was 180 feet deep and 52 feet wide, containing an 85-foot Atlas missile built by General Dynamics. Each missile carried a 4.5 megaton nuclear warhead capable of reaching Russia in about 30 minutes. Although the base never launched its 12 missiles, personnel of Strategic Air Command’s 578th Strategic Missile Squadron, which began operating the system in 1962, remained prepared for action, and all silos were armed and ready to launch during the Cuban Missile Crisis of October 1962. The Atlas ICBM mission ended in 1965, after which the underground silos and communications pits were salvaged and abandoned.