Central African President David Dacko is ousted from power in a bloodless military coup led by General André Kolingba.
World War II: Launch of Operation Ratweek, complicating German retreat.
World War II: Germany and Slovakia invade Poland, beginning the European phase of World War II.
J. Robert Oppenheimer and his student Hartland Snyder publish the Oppenheimer–Snyder model, proving for the first time in contemporary physics how black holes could develop.
The Tremont Street Subway in Boston opens, becoming the first underground rapid transit system in North America.
Emma Nutt becomes the world's first female telephone operator when she is recruited by Alexander Graham Bell to the Boston Telephone Dispatch Company.
Franco-Prussian War: The Battle of Sedan is fought, resulting in a decisive Prussian victory.
American Civil War: The Battle of Jonesborough, alongside the overall Atlanta campaign, culminates in a Union victory for General William T. Sherman as Confederate General John Bell Hood orders the evacuation of Atlanta.
Narcissa Whitman, one of the first English-speaking white women to settle west of the Rocky Mountains, arrives at Walla Walla, Washington.
Claudio Monteverdi's musical work Vespro della Beata Vergine (Vespers for the Blessed Virgin) is first published, printed in Venice and dedicated to Pope Paul V.
Adi Granth, now known as Guru Granth Sahib, the holy scripture of Sikhs, is first installed at Harmandir Sahib.
The Spanish fort of Sancti Spiritu, the first one built in modern Argentina, is destroyed by indigenous people.