NASA's Mariner 10 became the first spacecraft to fly past Venus en route to Mercury, using the planet's gravity to bend its trajectory.

NASA's Skylab 4 crew splashed down in the Pacific after a record-breaking 84 days in orbit, the longest human spaceflight to date at the time.

A federal grand jury secretly named President Richard Nixon an unindicted co-conspirator in the Watergate cover-up, a fact kept sealed for months.

NASA's Mariner 10 became the first spacecraft to fly past Mercury, transmitting the first close-up images ever taken of the solar system's innermost planet.

Hank Aaron hit his 715th career home run in Atlanta, surpassing Babe Ruth's long-standing record amid death threats and racist hate mail.

A near-bloodless military coup in Lisbon toppled Portugal's decades-long authoritarian Estado Novo regime, as civilians placed carnations in soldiers' rifle barrels.

The House Judiciary Committee opened formal impeachment hearings against President Richard Nixon over the Watergate scandal, broadcast to a riveted nation.

Farmers digging a well near Xi'an strike the buried head of a life-sized clay soldier, beginning the discovery of Qin Shi Huang's 8,000-warrior funerary army.

India conducts its first nuclear weapons test, codenamed Smiling Buddha, at the Pokhran Test Range, becoming the sixth nation with nuclear capability.

Swedish group ABBA won the Eurovision Song Contest in Brighton with 'Waterloo,' launching one of pop music's most successful careers.

A pack of Wrigley's gum became the first retail item scanned with a UPC barcode at a supermarket in Troy, Ohio, ushering in the era of automated retail.

NASA's Skylab 4 astronauts returned to Earth after 84 days in orbit, then the longest spaceflight in history, having staged a one-day strike over their grueling schedule.

Richard Nixon told the American public in a televised address that he would resign the presidency the next day, the first U.S. president ever to do so.

Portugal formally recognized the independence of Guinea-Bissau, ending centuries of colonial rule after a grinding anti-colonial guerrilla war.

Paleoanthropologist Donald Johanson and student Tom Gray discover the 3.2-million-year-old hominin skeleton nicknamed 'Lucy' in Ethiopia's Afar region.

NASA's Mariner 10 probe makes its historic first flyby of Mercury, returning humanity's first close-up images of the solar system's innermost planet.

Paleoanthropologist Donald Johanson found a 3.2-million-year-old hominid skeleton in Ethiopia's Afar region, later named Lucy.

Engineers at Xerox PARC continued refining the Alto personal computer's bitmap display and mouse-driven interface, technology that would later define modern computing.