June 20 in Military History

The Continental Congress adopts the Great Seal of the United States, featuring the bald eagle clutching arrows and an olive branch, symbols of war and peace that would adorn military standards for centuries.

The 18-year-old Victoria becomes Queen of the United Kingdom, beginning a 63-year reign that will see the British military expand the empire to its greatest extent.

In the weeks after the Battle of Hampton Roads, the U.S. Navy evaluates combat data from USS Monitor's revolving turret design, informing the follow-on Passaic-class monitors and establishing the turret as the future of warship armament.

The War Department reorganizes the Air Corps into the U.S. Army Air Forces (USAAF), giving air power semi-autonomous status under Commanding General Henry "Hap" Arnold.

President Roosevelt orders 6,000 federal troops into Detroit to quell a race riot that has killed 34 people, highlighting the racial tensions that plagued the American home front during World War II.

Admiral Mitscher orders Task Force 58 to illuminate its ships to guide home pilots returning from a long-range strike against the Japanese fleet, risking submarine and air attack to save his aviators.

Vice Admiral Marc Mitscher launches a 216-plane dusk strike at extreme range against the retreating Japanese Mobile Fleet, closing the Battle of the Philippine Sea with a sinking of Hiyo and heavy damage to Zuikaku.

Following North Korea's June 25 invasion, the U.S. Army rushes the understrength Task Force Smith from Japan to delay the advancing Korean People's Army, an early warning of the cost of postwar demobilization.

North American X-15 research aircraft reaches approximately 4,105 mph, or Mach 6.02, during a test flight out of Edwards Air Force Base, extending the envelope for hypersonic flight research.

The United States and Soviet Union agree to establish a direct communications link, the "Hot Line", between Washington and Moscow to reduce the risk of accidental nuclear war.