When Apollo 11. Landing on the Moon.

On July 20, 1969, humans walked on another world for the first time in history, achieving President John F. Kennedy's goal in 1961, before Americans had even orbited the Earth. After a landing that included dodging a lunar crater and boulder field just before touchdown, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin explored the area around their lunar landing site for more than two hours.

When the lunar module landed at 4:17 p.m. EDT, only 30 seconds of fuel remained. Armstrong radioed "Houston, Tranquility Base here. The Eagle has landed." Mission control erupted in celebration as the tension broke, and a controller told the crew "You got a bunch of guys about to turn blue, we're breathing again."