Croatians vote for independence in a referendum.

Mars probe program: ''Mars 2'' is launched by the Soviet Union.

A birthday salute to U.S. President John F. Kennedy takes place at Madison Square Garden, New York City. The highlight is Marilyn Monroe's rendition of ''Happy Birthday''.

Venera program: ''Venera 1'' becomes the first man-made object to fly-by another planet by passing Venus (the probe had lost contact with Earth a month earlier and did not send back any data).

A barge containing munitions destined for Pakistan explodes in the harbor at South Amboy, New Jersey, devastating the city.

World War II: British Prime Minister Winston Churchill and U.S. President Franklin D. Roosevelt set Monday, May 1, 1944 as the date for the Normandy landings ("D-Day"). It would later be delayed over a month due to bad weather.

The Young Pioneer organization of the Soviet Union is established.

The U.S. Congress passes the Emergency Quota Act establishing national quotas on immigration.

Mustafa Kemal Atatürk lands at Samsun on the Anatolian Black Sea coast, initiating what is later termed the Turkish War of Independence. The anniversary of this event is also regarded as a date of remembrance for Pontic Greeks on the Greek genocide.

Oscar Wilde is released from Reading Gaol.

American Civil War: the Battle of Spotsylvania Court House ends.

Mexican-American War: Mexico ratifies the Treaty of Guadalupe Hidalgo thus ending the war and ceding California, Nevada, Utah and parts of four other modern-day U.S. states to the United States for $15 million USD.

U.S. President John Quincy Adams signs the Tariff of 1828 into law, protecting wool manufacturers in the United States.

Napoleon Bonaparte founds the Légion d'Honneur.

New England's Dark Day: A combination of thick smoke and heavy cloud cover causes complete darkness to fall on Eastern Canada and the New England area of the United States at 10:30 A.M.

King George II of Great Britain grants the Ohio Company a charter of land around the forks of the Ohio River.

An Act of Parliament declaring England a Commonwealth is passed by the Long Parliament. England would be a republic for the next eleven years.

Thirty Years' War: French forces under the duc d'Enghien decisively defeat Spanish forces at the Battle of Rocroi, marking the symbolic end of Spain as a dominant land power.

Queen Elizabeth I of England orders the arrest of Mary, Queen of Scots.

Anne Boleyn, the second wife of Henry VIII of England, is beheaded for adultery, treason, and incest.

French explorer Jacques Cartier sets sail on his second voyage to North America with three ships, 110 men, and Chief Donnacona's two sons (whom Cartier had kidnapped during his first voyage).

Catherine of Aragon, is married by proxy to Arthur Tudor, Prince of Wales. Catherine is 13 and Arthur is 12.