On April 12

A fire broke out near Valparaíso, Chile, eventually destroying at least 2,500 homes and leaving approximately 11,000 people homeless (damage pictured).

Four Chadian soldiers were killed in a suicide bombing by jihadist rebels in Kidal, Mali.

The Guinea-Bissau military seized control in a coup amid a presidential election, later handing power to a transitional administration under Manuel Serifo Nhamadjo.

Husband-and-wife law partners Laurence Canter and Martha Siegel posted the first massive commercial spam on Usenet.

Bosnian War: NATO forces began Operation Deny Flight to enforce a no-fly zone over Bosnia and Herzegovina ordered by the United Nations Security Council.

Harold Washington was elected as the first African-American mayor of Chicago.

Canadian athlete Terry Fox embarked on an east-to-west "Marathon of Hope" from St. John's, Newfoundland and Labrador, with a prosthetic leg to raise funds for cancer research.

About 1,700 gravediggers in New York City began a 12-week strike, causing a delay in the burial of roughly 1,400 bodies in the city.

Aboard Vostok 1, Soviet cosmonaut Yuri Gagarin performed the first human spaceflight, completing one orbit of Earth in 108 minutes.

SMS Zrínyi, one of the last pre-dreadnoughts built by the Austro-Hungarian Navy, was launched in Trieste.

Confederate forces began a bombardment of Fort Sumter in the harbor of Charleston, South Carolina, starting the American Civil War.

The Broughton Suspension Bridge near Manchester, England, collapsed reportedly because of mechanical resonance induced by troops marching in step across it.

Greek War of Independence: Ottoman troops began a massacre of tens of thousands of Greeks (depicted) on the island of Chios.

The Froberg mutiny of Greek and Albanian troops in British service ended with the explosion of the gunpowder magazine at Fort Ricasoli, Malta.

American Revolution: The North Carolina Provincial Congress passed the Halifax Resolves, the first official action in the American colonies calling for independence from Great Britain.

Troops of the Fourth Crusade entered Constantinople and began a sack of the city, temporarily dissolving the Byzantine Empire.

King Edwin of Northumbria was baptised by Bishop Paulinus of York.