In a major turn of events in World War II, Italy declared war on Germany. (1943) Initially, Italy had sided with the Axis powers while under Mussolini's rule. Once he was removed from power, however, his chief of staff General Pietro Badaglio began negotiations with US President Dwight Eisenhower. Italy shifted alliances and joined the Allied forces for the duration of the war.
The Whirlpool Galaxy was discovered. (1773) The spiral galaxy was discovered by French astronomer Charles Messier. The galaxy, which is about 23 million light years from Earth, can be clearly viewed through binoculars, making it a popular object of observation for amateur astronomers.
The US Senate refused to ratify the Comprehensive Test Ban Treaty (CTBT). (1999) The treaty calls for a ban on nuclear explosions of any kind. The United Nations adopted the treaty in 1996, but many countries have yet to ratify it.
The longitudinal Universal Time meridian was established. (1884) With worldwide travel becoming more common, an international time standard was in demand. The International Meridian Conference established the meridian as the local time at the Royal Greenwich Observatory in England.
Construction began on the US White House with the laying of the cornerstone. (1792) The White House was originally called the United States Executive Mansion, but was renamed in 1818. The estate took eight years to complete.
The US Navy was created. (1775) The US Continental Congress, in response to intelligence information that a British naval fleet was en route at the beginning of the American Revolutionary War, established the Continental Navy. The military institution later became the US Navy.
A comet was discovered through photography for the first time. (1892) Edward Emerson Barnard, an American astronomer, shot a photo of the D/1892 T1 comet, the first of its kind.
The British defeat during the "Battles of Saratoga" provoked France to join the American Revolutionary War, fighting against the British. (1777) In a major turn of the war, the US military gained the support of France in its battle for independence.
The first cellular phone network in the US was launched. (1983) Ameritech Mobile Communications, which later became AT&T, launched the first public cellular network in Chicago, Illinois.
The Ebola virus was identified. (1976) Dr. Frederick Murphy, the Chief of Viropathology at the Center for Disease Control and Prevention, was able to microscopically photograph the virus.
The Republic of Texas adopted a constitution in an effort to become a US state. (1845) The US Congress approved the republic's constitution, and Texas was admitted to the Union on December 29, 1845.