The Indonesian Navy submarine Nanggala sank, resulting in the deaths of all 53 people on board.
The city of Flint, Michigan, U.S., changed its water source to the Flint River, which exposed residents to lead poisoning.
Ukraine and Russia signed the Kharkiv Pact, extending the Russian lease on naval facilities in Crimea.
South Vietnamese president Nguyễn Văn Thiệu resigned on hearing of the fall of Xuân Lộc, the last battle of the Vietnam War.
In response to a dispute over wheat production quotas, Leonard Casley declared his 75 km2 (29 sq mi) farm in Western Australia to be an independent country as the Hutt River Province.
The Century 21 Exposition, the first world's fair in the United States since World War II, opened in Seattle.
United Airlines Flight 736 collided with a U.S. Air Force fighter jet over southern Nevada, resulting in the deaths of all 49 people on board both aircraft.
The "Surgeon's Photograph", purportedly showing the Loch Ness Monster (later revealed to be a hoax), was published in the Daily Mail.
Forces of the Republic of Texas led by Sam Houston defeated the Mexican troops of General Antonio López de Santa Anna in the Battle of San Jacinto, the decisive and final battle of the Texas Revolution.
The Ladies of Trenton social club hosted a reception (depicted) for President-elect George Washington as he journeyed to New York City for his first inauguration.
J. S. Bach's cantata Bleib bei uns, denn es will Abend werden, was first performed on Easter Monday.
The Wignacourt Aqueduct (pictured) in Malta was inaugurated, and was used to carry water to Valletta for about 300 years.
Ælfric of Abingdon was appointed Archbishop of Canterbury
A debt was pardoned by the chief of Tondo on the island of Luzon and recorded on the Laguna Copperplate Inscription, the earliest known calendar-dated document found in the Philippines.
Forces led by Mark Antony fought the Battle of Mutina against those of Decimus Brutus, one of Julius Caesar's assassins.
Romulus and Remus (depicted) legendarily founded the city of Rome, according to the calculations of ancient Roman scholar Varro Reatinus.
Indonesian Navy submarine KRI Nanggala (402) sinks in the Bali Sea during a military drill, killing all 53 on board.
Eight bombs explode at churches, hotels, and other locations in Sri Lanka on Easter Sunday, killing at least 269.
The American city of Flint, Michigan switches its water source to the Flint River, beginning the ongoing Flint water crisis which has caused lead poisoning in up to 12,000 people, and at least 12 deaths from Legionnaires' disease, ultimately leading to criminal indictments against 15 people, five of whom have been charged with involuntary manslaughter.
Two trains are involved in a head-on collision near Sloterdijk, Amsterdam, in the Netherlands, killing one person and injuring 116 others.
The controversial Kharkiv Pact (Russian Ukrainian Naval Base for Gas Treaty) is signed in Kharkiv, Ukraine, by Ukrainian President Viktor Yanukovych and Russian President Dmitry Medvedev; it was unilaterally terminated by Russia on March 31, 2014.
Five suicide car bombers target police stations in and around Basra, killing 74 people and wounding 160.
The Supreme Court in La Paz, Bolivia, sentences former dictator Luis García Meza to 30 years in jail without parole for murder, theft, fraud and violating the constitution.
Tiananmen Square protests of 1989: In Beijing, around 100,000 students gather in Tiananmen Square to commemorate Chinese reform leader Hu Yaobang.
The Tamil Tigers are blamed for a car bomb that detonates in the Sri Lankan capital city of Colombo, killing 106 people.
The compound of the militant group The Covenant, The Sword, and the Arm of the Lord surrenders to federal authorities in Arkansas after a two-day government siege.
Baseball: Rollie Fingers of the Milwaukee Brewers becomes the first pitcher to record 300 saves.
Annie opens on Broadway.
Vietnam War: President of South Vietnam Nguyễn Văn Thiệu flees Saigon, as Xuân Lộc, the last South Vietnamese outpost blocking a direct North Vietnamese assault on Saigon, falls.
Astronauts John Young and Charles Duke fly Apollo 16's Apollo Lunar Module to the Moon's surface, the fifth NASA Apollo Program crewed lunar landing.
A few days before the general election in Greece, Colonel George Papadopoulos leads a coup d'état, establishing a military regime that lasts for seven years.
Rastafari movement: Haile Selassie of Ethiopia visits Jamaica, an event now celebrated as Grounation Day.
The 1964–1965 New York World's Fair opens for its second and final season.
A Transit-5bn satellite fails to reach orbit after launch; as it re-enters the atmosphere, 2.1 pounds (0.95 kg) of radioactive plutonium in its SNAP RTG power source is widely dispersed.
The first election of the Universal House of Justice is held, marking its establishment as the supreme governing institution of the Baháʼí Faith.
The Seattle World's Fair (Century 21 Exposition) opens. It is the first World's Fair in the United States since World War II.
Brasília, Brazil's capital, is officially inaugurated. At 09:30, the Three Powers of the Republic are simultaneously transferred from the old capital, Rio de Janeiro.
United Air Lines Flight 736 collides with a United States Air Force fighter jet near Arden, Nevada in what is now Enterprise, Nevada.
Secretary's Day (now Administrative Professionals' Day) is first celebrated.
The Nainital wedding massacre occurs, killing 22 members of the Harijan caste.
United Nations Security Council Resolution 47 relating to Kashmir conflict is adopted.
The U.S. Weather Bureau records that a tornado which struck Timber Lake, South Dakota was 4 miles (6.4 km), among the widest tornadoes on record.
World War II: Soviet forces south of Berlin at Zossen attack the German High Command headquarters.
The "Surgeon's Photograph", the most famous photo allegedly showing the Loch Ness Monster, is published in the Daily Mail (in 1994, it is revealed to be a hoax).
Al-Baqi cemetery, former site of the mausoleum of four Shi'a Imams, is leveled to the ground by Wahhabis.
World War I: German fighter ace Manfred von Richthofen, better known as "The Red Baron", is shot down and killed over Vaux-sur-Somme in France.
Ypiranga incident: A German arms shipment to Mexico is intercepted by the U.S. Navy near Veracruz.
Spanish–American War: The United States Navy begins a blockade of Cuban ports. When the U.S. Congress issued a declaration of war on April 25, it declared that a state of war had existed from this date.
Norway formally adopts the Krag–Jørgensen bolt-action rifle as the main arm of its armed forces, a weapon that would remain in service for almost 50 years.
Australian labour movement: Stonemasons and building workers on building sites around Melbourne march from the University of Melbourne to Parliament House to achieve an eight-hour day.
Texas Revolution: The Battle of San Jacinto: Republic of Texas forces under Sam Houston defeat troops under Mexican General Antonio López de Santa Anna.
Benderli Ali Pasha arrives in Constantinople as the new Grand Vizier of the Ottoman Empire; he remains in power for only nine days before being sent into exile.
Two Austrian army corps are driven from Landshut by a First French Empire army led by Napoleon as two French corps to the north hold off the main Austrian army on the first day of the Battle of Eckmühl.
Action of 21 April 1806: A French frigate escapes British forces off the coast of South Africa.
Twelve thousand Wahhabis sack Karbala, killing over three thousand inhabitants.
War of the First Coalition: In the climax of the Montenotte Campaign, Napoleon Bonaparte decisively defeats the army of Piedmont at the Battle of Mondovi, leading to Piedmont's surrender a week later and decisively turning the Italian campaign in France's favor.
Tiradentes, a revolutionary leading a movement for Brazil's independence, is hanged, drawn and quartered.
John Adams sworn in as first US Vice President (nine days before George Washington).
George Washington's reception at Trenton is hosted by the Ladies of Trenton as he journeys to New York City for his first inauguration.
The city of Rattanakosin, now known internationally as Bangkok, is founded on the eastern bank of the Chao Phraya River by King Buddha Yodfa Chulaloke.
The Wignacourt Aqueduct is inaugurated in Malta.
The last ruler of the Lodi dynasty, Ibrahim Lodi is defeated and killed by Babur in the First Battle of Panipat.
Henry VIII ascends the throne of England on the death of his father, Henry VII.
The three-day Lisbon Massacre comes to an end with the slaughter of over 1,900 suspected Jews by Portuguese Catholics.
The Diocese of Pisa is elevated to the rank of metropolitan archdiocese by Pope Urban II
The Laguna Copperplate Inscription (the earliest known written document found in what is now the Philippines): the Commander-in-Chief of the Kingdom of Tondo, as represented by the Honourable Jayadewa, Lord Minister of Pailah, pardons from all debt the Honourable Namwaran and his relations.
Battle of Mutina: Mark Antony is again defeated in battle by Aulus Hirtius, who is killed. Antony fails to capture Mutina and Decimus Brutus is murdered shortly after.
Romulus founds Rome (traditional date).
Hyein, South Korean singer
Princess Isabella of Denmark, daughter of King Frederik X and Queen Mary of Denmark
Xavi Simons, Dutch footballer
Choi Hyun-suk, South Korean rapper
Jarrett Allen, American basketball player
Mikel Oyarzabal, Spanish footballer
Arianne Hartono, Dutch tennis player
Ludwig Augustinsson, Swedish footballer
Isco, Spanish footballer
Joc Pederson, American baseball player
Nikki Cross, Scottish wrestler
Ricky Berens, American swimmer
Jencarlos Canela, American singer-songwriter and actor
Tarvaris Jackson, American football player (died 2020)
Kim Wall, British sprinter
Tony Romo, American football player and announcer
Virginie Basselot, French chef
James McAvoy, Scottish actor
Gyula Koi, Hungarian scholar and educator
Jamie Salé, Canadian figure skater
Petero Civoniceva, Fijian-Australian rugby league player
David Peachey, Australian rugby league player
Steve Backshall, English naturalist, writer, and television presenter
Michael Turner, American author and illustrator (died 2008)
Rob Riggle, American actor and comedian
Toby Stephens, English actor
Fiona Kelleghan, American academic, critic and librarian
Ken Caminiti, American baseball player (died 2004)
David Servan-Schreiber, French physician, neuroscientist, and author (died 2011)
Tim Jacobus, American illustrator and painter
Robert Smith, English singer-songwriter and guitarist
Andie MacDowell, American model, actress, and producer
Yoshito Usui, Japanese illustrator (died 2009)
Michael Zarnock, American author
Hervé Le Tellier, French linguist and author
Herbert Wetterauer, German painter, sculptor, and author
Peter Kosminsky, English director, producer, and screenwriter
Phillip Longman, German-American demographer and journalist
Murathan Mungan, Turkish author, poet, and playwright
Ebiet G. Ade, Indonesian singer-songwriter and guitarist
James Morrison, American actor, director, producer, and screenwriter
Mike Wingfield, South African academic and scientist
John Brumby, Australian politician, 45th Premier of Victoria
Gerald Early, American author and academic
Cheryl Gillan, British businesswoman and politician, Secretary of State for Wales (died 2021)
Tony Danza, American actor and producer
Michael Freedman, American mathematician and academic
Bob Varsha, American sportscaster
Steve Vickers, Canadian ice hockey player
Shivaji Satam, Indian actor
Patti LuPone, American actress and singer
Gary Condit, American businessman and politician
Paul Davis, American singer-songwriter and musician (died 2008)
Josef Flammer, Swiss ophthalmologist
Dieter Fromm, German runner
Al Bumbry, American baseball player
Iggy Pop, American singer-songwriter, producer, and actor
John Weider, English bass player
Srinivasaraghavan Venkataraghavan, Indian cricketer and umpire
Mark Wainberg, Canadian researcher and HIV/AIDS activist (died 2017)
Diana Darvey, English actress, singer and dancer (died 2000)
Geoffrey Palmer, New Zealand politician, 33rd Prime Minister of New Zealand
David Boren, American lawyer and politician, 21st Governor of Oklahoma (died 2025)
Jacques Caron, Canadian ice hockey player and coach
Souleymane Cissé, Malian director, producer, and screenwriter
John McCabe, English pianist and composer (died 2015)
Sister Helen Prejean, American nun, activist, and author
Reni Santoni, American actor (died 2020)
Gary Peters, American baseball player (died 2023)
Ben Zinn, Israeli-born American academic and former international soccer player
James Dobson, American evangelist, psychologist, and author, founded Focus on the Family
Reg Fleming, Canadian-American ice hockey player (died 2009)
Charles Grodin, American actor and talk show host (died 2021)
Thomas Kean, American academic and politician, 48th Governor of New Jersey
Edelmiro Amante, Filipino lawyer and politician (died 2013)
Easley Blackwood, Jr., American pianist, composer, and educator (died 2023)
Ignatius Zakka I Iwas, Iraqi patriarch (died 2014)
Slide Hampton, African-American trombonist and composer (died 2021)
Elaine May, American actress, comedian, director, and screenwriter
Angela Mortimer, English tennis player
Morgan Wootten, American high school basketball coach (died 2020)
Hilda Hilst, Brazilian author, poet, and playwright (died 2004)
Silvana Mangano, Italian actress (died 1989)
Dieter Roth, German-Swiss illustrator and sculptor (died 1998)
Jack Taylor, English footballer and referee (died 2012)
Jack Evans, Welsh-Canadian ice hockey player and coach (died 1996)
Ahmed Arif, Turkish poet and author (died 1991)
Elizabeth II, Queen of the United Kingdom and her other realms (died 2022)
Arthur Rowley, English footballer, manager, and cricketer (died 2002)
Anthony Mason, Australian soldier and judge, 9th Chief Justice of Australia
John Swinton of Kimmerghame, English general and politician, Lord Lieutenant of Berwickshire (died 2018)
Ira Louvin, American singer-songwriter and mandolin player (died 1965)
John Mortimer, English lawyer and author (died 2009)
Alistair MacLean, Scottish novelist and screenwriter (died 1987)
Allan Watkins, Welsh-English cricketer (died 2011)
Don Cornell, American singer (died 2004)
Roger Doucet, Canadian tenor (died 1981)
Licio Gelli, Italian financer (died 2015)
Eddy Christiani, Dutch singer-songwriter and guitarist (died 2016)
Estella B. Diggs, American businesswoman and politician (died 2013)
Garrett Hardin, American ecologist, author, and academic (died 2003)
Anthony Quinn, Mexican-American actor (died 2001)
Angelo Savoldi, Italian-American wrestler and promoter, co-founded International World Class Championship Wrestling (died 2013)
Norman Parkinson, English photographer (died 1990)
Eve Arnold, Russian-American photojournalist (died 2012)
Marcel Camus, French director and screenwriter (died 1982)
Ivan Combe, American businessman, developed Clearasil (died 2000)
Kemal Satır, Turkish physician and politician (died 1991)
Pat Brown, American lawyer and politician, 32nd Governor of California (died 1996)
Jean Hélion, French painter (died 1987)
Odilo Globocnik, Italian-Austrian SS officer (died 1945)
Luis Saslavsky, Argentinian director, producer, and screenwriter (died 1995)
Randall Thompson, American composer and academic (died 1984)
Maurice Wilson, English soldier, pilot, and mountaineer (died 1934)
Odd Lindbäck-Larsen, Norwegian Army general and war historian (died 1975)
Romeo Bertini, Italian runner (died 1973)
Freddie Dixon, English motorcycle racer and racing driver (died 1956)
Marcel Boussac, French businessman (died 1980)
Paul Karrer, Russian-Swiss chemist and academic, Nobel Prize laureate (died 1971)
Efrem Zimbalist, Sr., Russian-American violinist, composer, and conductor (died 1985)
Joe McCarthy, American baseball manager (died 1978)
Tatu Kolehmainen, Finnish runner (died 1967)
Percy Williams Bridgman, American physicist and academic, Nobel Prize laureate (died 1961)
Vincent Scotto, French composer and actor (died 1952)
Edwin Stanton Porter, American director, producer, and screenwriter (died 1941)
Alfred Henry Maurer, American painter (died 1932)
Mary Rogers Miller, American author and educator (died 1971)
Max Weber, German economist and sociologist (died 1920)
William Stang, German-American bishop (died 1907)
John Muir, Scottish-American environmentalist and author (died 1914)
Fredrik Bajer, Danish lieutenant and politician, Nobel Prize laureate (died 1922)
Charlotte Brontë, English novelist and poet (died 1855)
Angela Burdett-Coutts, 1st Baroness Burdett-Coutts, English art collector and philanthropist (died 1906)
Alson Sherman, American merchant and politician, 8th Mayor of Chicago (died 1903)
John Putnam Chapin, American politician, 10th Mayor of Chicago (died 1864)
Manuel Blanco Encalada, Spanish-Chilean admiral and politician, 1st President of Chile (died 1876)
Reginald Heber, English priest (died 1821)
Alexander Anderson, Scottish-American illustrator and engraver (died 1870)
Jean-Baptiste Biot, French physicist, astronomer, and mathematician (died 1862)
Pierre-Alexandre-Laurent Forfait, French engineer, hydrographer, and politician, French Minister of Marine and the Colonies (died 1807)
Humphry Repton, English gardener and author (died 1818)
Antonín Kammel, Czech violinist and composer (died 1788)
Louis de Noailles, French general (died 1793)
Wilhelmine Amalia of Brunswick-Lüneburg (died 1742)
John Law, Scottish economist (died 1729)
Michel Rolle, French mathematician and academic (died 1719)
Joseph Vaz, Sri Lankan priest, missionary, and saint (died 1711)
Simon de la Loubère, French mathematician, poet, and diplomat (died 1729)
Francesco Maidalchini, Catholic cardinal (died 1700)
Pieter Gerritsz van Roestraten, Dutch-English painter (died 1700)
Jan van Riebeeck, Dutch founder of Cape Town (died 1677)
Ludovico Carracci, Italian painter and etcher (died 1619)
Marco Antonio Bragadin, Venetian lawyer and military officer (died 1571)
Ulrich von Hutten, German religious reformer (died 1523)
Sancho VI, king of Navarre (died 1194)
Pope Francis (born 1936)
Terry A. Anderson, American journalist (born 1947)
Polly Higgins, Scottish barrister, author and environmental lobbyist (born 1968)
Nabi Tajima, Japanese supercentenarian (born 1900)
Ugo Ehiogu, English footballer (born 1972)
Prince, American singer-songwriter, guitarist, producer, and actor (born 1958)
George H. Heilmeier, American engineer (born 1936)
Win Tin, Burmese journalist and politician, co-founded the National League for Democracy (born 1930)
Shakuntala Devi, Indian mathematician and astrologer (born 1929)
Leopold Engleitner, Austrian Holocaust survivor, author, and educator (born 1905)
Doris Betts, American author and academic (born 1932)
Catharina Halkes, Dutch theologian and academic (born 1920)
Gustav Lorentzen, Norwegian singer-songwriter and guitarist (born 1947)
Juan Antonio Samaranch, Spanish businessman, seventh President of the International Olympic Committee (born 1920)
Kanagaratnam Sriskandan, Sri Lankan-English engineer and civil servant (born 1930)
Zhang Chunqiao, Chinese writer and politician, member of the Gang of Four (born 1917)
Nina Simone, American singer-songwriter, pianist, and activist (born 1933)
Buddy Rogers, American actor (born 1904)
Jean-François Lyotard, French sociologist and philosopher (born 1924)
Abdul Hafeez Kardar, Pakistani cricketer (born 1925)
Jimmy Snyder, American sportscaster (born 1919)
Väinö Linna, Finnish author (born 1920)
Willi Boskovsky, Austrian violinist and conductor (born 1909)
Erté, Russian-French illustrator (born 1892)
Gustav Bergmann, Austrian-American philosopher from the Vienna Circle (born 1906)
Marjorie Eaton, American painter and actress (born 1901)
Salah Jahin, Egyptian poet, playwright, and composer (born 1930)
Rudi Gernreich, Austrian-American fashion designer, created the monokini (born 1922)
Tancredo Neves, Brazilian banker and politician, Prime Minister of Brazil (born 1910)
Marcel Janco, Romanian-Israeli artist (born 1895)
Hristo Prodanov, Bulgarian engineer and mountaineer (born 1943)
Walter Slezak, Austrian-American actor and singer (born 1902)
Alexander Oparin, Russian biochemist and academic (born 1894)
Sohrab Sepehri, Iranian poet and painter (born 1928)
Sandy Denny, English singer-songwriter (born 1947)
Thomas Wyatt Turner, American biologist and academic (born 1877)
Gummo Marx, American vaudevillian and talent agent (born 1892)
Arthur Fadden, Australian accountant and politician, 13th Prime Minister of Australia (born 1894)
Kemal Tahir, Turkish journalist and author (born 1910)
François Duvalier, Haitian physician and politician, 40th President of Haiti (born 1907)
Edward Victor Appleton, English-Scottish physicist and academic, Nobel Prize laureate (born 1892)
Charles MacArthur, American playwright and screenwriter (born 1895)
Emil Leon Post, Polish-American mathematician and logician (born 1897)
Leslie Banks, American actor, director and producer (born 1890)
Aldo Leopold, American ecologist and author (born 1887)
John Maynard Keynes, English economist and philosopher (born 1883)
Walter Model, German field marshal (born 1891)
Fritz Manteuffel, German gymnast (born 1875)
Allama Muhammad Iqbal, Pakistani National philosopher and poet (born 1877)
Friedrich Gustav Piffl, Bohemian cardinal (born 1864)
Robert Bridges, English poet and author (born 1844)
Eleonora Duse, Italian actress (born 1858)
Manfred von Richthofen, German captain and pilot (born 1892)
Mark Twain, American novelist, humorist, and critic (born 1835)
Vikramatji Khimojiraj, Indian ruler (born 1819)
Sir Robert Bateson, 1st Baronet, Irish politician (born 1782)
Ivan Nabokov, Russian general (born 1787)
Johann Friedrich Pfaff, German mathematician and academic (born 1765)
Joseph Winston, American soldier and politician (born 1746)
Francesco Zerafa, Maltese architect (born 1679)
Thomas Tickell, English poet and author (born 1685)
Prince Eugene of Savoy (born 1663)
Robert Beverley, Jr., English historian and author (born 1673)
Antoine Hamilton, Irish-French soldier and author (born 1646)
Philippe de La Hire, French mathematician and astronomer (born 1640)
Jean Racine, French playwright and poet (born 1639)
Jan Boeckhorst, Flemish painter (born c. 1604)
Yagyū Jūbei Mitsuyoshi, Japanese samurai (born 1607)
Sen no Rikyū, Japanese exponent of the tea ceremony (born 1522)
Cosimo I de' Medici, Grand Duke of Tuscany (born 1519)
Petrus Apianus, German mathematician and astronomer (born 1495)
Henry VII of England (born 1457)
John Wittlebury, English politician (born 1333)
Frederick IV, Duke of Lorraine (born 1282)
Maria of Montpellier, Lady of Montpellier, Queen of Aragon (born 1182)
Peter Abelard, French philosopher and theologian (born 1079)
Stephen, Count of Tréguier Breton noblemen (born c. 1058/62)
Anselm of Canterbury, Italian-English archbishop and saint (born 1033)
Pope Alexander II
Bajkam, de facto regent of the Abbasid Caliphate
Bardas, de facto regent of the Byzantine Empire
Odgar, Frankish archbishop of Mainz
Liuvigild, king of the Visigoths
Emperor Xian of Han, Chinese emperor (born 181)
Christian feast day: Abdecalas
Christian feast day: Anastasius Sinaita
Christian feast day: Anselm of Canterbury
Christian feast day: Beuno
Christian feast day: Conrad of Parzham
Christian feast day: Holy Infant of Good Health
Christian feast day: Shemon Bar Sabbae
Christian feast day: Wolbodo
Christian feast day: April 21 (Eastern Orthodox liturgics)
Natale di Roma (Rome)
Parilia (ancient Rome)
Civil Service Day (India)
Grounation Day (Rastafari)
National Tea Day (United Kingdom)
National Tree Planting Day (Kenya)
San Jacinto Day (Texas)