August 21 in history — What Happened Today in History

A bomb exploded in the Liberal Party campaign rally in Plaza Miranda, Manila, Philippines with several anti-Marcos political candidates injured.

Cold War: Nicolae Ceaușescu, leader of the Socialist Republic of Romania, publicly condemns the Soviet-led Warsaw Pact invasion of Czechoslovakia, encouraging the Romanian population to arm itself against possible Soviet reprisals.

James Anderson Jr. posthumously receives the first Medal of Honor to be awarded to an African American U.S. Marine.

The Socialist Republic of Romania is proclaimed, following the adoption of a new constitution.

Xá Lợi Pagoda raids: The Army of the Republic of Vietnam Special Forces loyal to Ngô Đình Nhu, brother of President Ngo Dinh Diem, vandalizes Buddhist pagodas across the country, arresting thousands and leaving an estimated hundreds dead.

United States President Dwight D. Eisenhower signs an executive order proclaiming Hawaii the 50th state of the Union. Hawaii's admission is currently commemorated by Hawaii Admission Day.

The Soviet Union successfully conducts a long-range test flight of the R-7 Semyorka, the first intercontinental ballistic missile.

Physicist Harry Daghlian is fatally irradiated in a criticality accident during an experiment with the Demon core at Los Alamos National Laboratory.

Dumbarton Oaks Conference, prelude to the United Nations, begins.

World War II: Canadian and Polish units capture the strategically important town of Falaise, Calvados, France.

World War II: During the Guadalcanal campaign, American forces defeat an attack by Imperial Japanese Army soldiers in the Battle of the Tenaru.

World War I: The Second Battle of the Somme begins.

World War I: The Battle of Charleroi, a successful German attack across the River Sambre that pre-empted a French offensive in the same area.

The Mona Lisa is stolen by Vincenzo Peruggia, a Louvre employee.

Six hundred American school teachers, Thomasites, arrived in Manila on the USAT Thomas.

The first successful adding machine in the United States is patented by William Seward Burroughs.

An F5 tornado strikes Rochester, Minnesota, leading to the creation of the Mayo Clinic.

The locals of Knock, County Mayo, Ireland report their having seen an apparition of the Virgin Mary. The apparition is later named "Our Lady of Knock" and the spot transformed into a Catholic pilgrimage site.

The American Bar Association is founded in Saratoga Springs, New York.

Lawrence, Kansas is destroyed by pro-Confederate guerrillas known as Quantrill's Raiders.

The Stadtpark, the first public park in Vienna, opens to the public.

The first of the Lincoln–Douglas debates is held in Ottawa, Illinois.

Tlingit Indians destroy Fort Selkirk, Yukon Territory.

Nat Turner leads black slaves and free blacks in a rebellion in Southampton County, Virginia, claiming the lives of 55 to 65 whites and about twice that number of blacks.

Jarvis Island is discovered by the crew of the ship, Eliza Frances.

Jean-Baptiste Bernadotte, Marshal of France, is elected Crown Prince of Sweden by the Swedish Riksdag of the Estates.

Battle of Vimeiro: British and Portuguese forces led by General Arthur Wellesley defeat the French forces under Major-General Jean-Andoche Junot near the village of Vimeiro, Portugal, the first Anglo-Portuguese victory of the Peninsular War.

Enslaved Africans in Saint-Domingue, led by Dutty Boukman, held a Vodou ceremony that became a pivotal act of resistance. This gathering sparked a mass uprising against slavery, marking the beginning of the Haitian Revolution.

RJ Mitte, American actor (died 2026)

Felipe Nasr, Brazilian race car driver

Leandro Bacuna, Dutch footballer

Jesse Rutherford, American singer and songwriter

Bo Burnham, American comedian, musician, actor, filmmaker and poet

Christian Vázquez, Puerto Rican baseball player

Charlison Benschop, Dutch footballer

James Davey, English rugby league player

Matteo Gentili, Italian footballer

Hayden Panettiere, American actress (died 2026)

Aleix Vidal, Spanish footballer

Robert Lewandowski, Polish footballer

Joanna Mitrosz, Polish rhythmic gymnast

Jimmy Evert, American tennis player and coach (born 1924)

Gerry Anderson, Irish radio and television host (born 1944)

Helen Bamber, English psychotherapist and academic (born 1925)

Steven R. Nagel, American colonel, engineer, and astronaut (born 1946)

Jean Redpath, Scottish singer-songwriter (born 1937)

Albert Reynolds, Irish businessman and politician, ninth Taoiseach of Ireland (born 1932)

Jean Berkey, American lawyer and politician (born 1938)

Sid Bernstein, American record producer (born 1918)

C. Gordon Fullerton, American colonel, engineer, and astronaut (born 1936)

Fred Martin, Scottish footballer (born 1929)

Enos Nkala, Zimbabwean politician, Zimbabwean Minister of Defence (born 1932)

Georg Leber, German soldier and politician, Federal Minister of Defence (born 1920)

J. Frank Raley Jr., American soldier and politician (born 1926)