Pluto, once believed to be the ninth planet, is discovered at the Lowell Observatory in Flagstaff, Arizona, by astronomer Clyde W. Tombaugh.

On March 12, 1930, Indian independence leader Mohandas Gandhi begins a defiant march to the sea in protest of the British monopoly on salt, his boldest act of civil disobedience yet against British rule in India.

A fire at an Ohio prison kills 320 inmates, some of whom burn to death when they are not unlocked from their cells. It is one of the worst prison disasters in American history.

Best known to his many fans for one of his most memorable screen incarnations—San Francisco Police Inspector “Dirty” Harry Callahan—the actor and Oscar-winning filmmaker Clint Eastwood is born on May 31, 1930, in San Francisco, California.

On July 7, 1930, building begins on the future site of the Hoover Dam. Over the next five years, a total of 21,000 men would work ceaselessly to produce what would be the largest dam of its time, as well as one of the largest manmade structures in the world.

On July 13, 1930, France defeats Mexico 4-1 and the United States defeats Belgium 3-0 in the first-ever World Cup football matches, played simultaneously in host city Montevideo, Uruguay. The World Cup has since become the world’s most watched sporting event.

On August 6, 1930, New York Supreme Court judge Joseph Force Crater vanished on the streets of Manhattan near Times Square. The dapper 41-year-old’s disappearance launched a massive investigation that captivated the nation, earning Crater the title of “the missingest man in New York.”

On October 5, 1930, a British dirigible crashes in Beauvais, France, killing all but seven people onboard. The airship, which was Great Britain’s biggest, had first been launched about a year earlier.