At 9:32 a.m. EDT, Apollo 11, the first U.S. lunar landing mission, is launched on a historic journey to the surface of the moon. After traveling 240,000 miles in 76 hours, Apollo 11 entered into a lunar orbit on July 19.

The next day, at 1:46 p.m., the lunar module Eagle, manned by astronauts Neil Armstrong and Edwin “Buzz” Aldrin, separated from the command module, where a third astronaut, Michael Collins, remained. Two hours later, the Eagle began its descent to the lunar surface, and at 4:18 p.m. the craft touched down on the southwestern edge of the Sea of Tranquility. Armstrong immediately radioed to Mission Control in Houston a famous message, “The Eagle has landed.” At 10:39 p.m., five hours ahead of the original schedule, Armstrong opened the hatch of the lunar module. Seventeen minutes later, at 10:56 p.m., Armstrong spoke the following words to millions listening at home: “That’s one small step for man, one giant leap for mankind.” A moment later, he stepped off the lunar module’s ladder, becoming the first human to walk on the surface of the moon.

Aldrin joined him on the moon’s surface at 11:11 p.m., and together they took photographs of the terrain, planted a U.S. flag, ran a few simple scientific tests, and spoke with President Richard M. Nixon via Houston. By 1:11 a.m. on July 21, both astronauts were back in the lunar module, and the hatch was closed. The two men slept that night on the surface of the moon, and at 1:54 p.m. the Eagle began its ascent back to the command module. Among the items left on the surface of the moon was a plaque that read: “Here men from the planet Earth first set foot on the moon–July 1969 A.D.–We came in peace for all mankind.” At 5:35 p.m., Armstrong and Aldrin successfully docked and rejoined Collins, and at 12:56 a.m. on July 22 Apollo 11 began its journey home, safely splashing down in the Pacific Ocean at 12:51 p.m. on July 24.

There would be five more successful lunar landing missions, and one unplanned lunar swing-by, Apollo 13. The last men to walk on the moon, astronauts Eugene Cernan and Harrison Schmitt of the Apollo 17 mission, left the lunar surface on December 14, 1972. The Apollo program was a costly and labor intensive endeavor, involving an estimated 400,000 engineers, technicians, and scientists, and costing $24 billion (close to $100 billion in today’s dollars). The expense was justified by President John F. Kennedy’s 1961 mandate to beat the Soviets to the moon, and after the feat was accomplished, ongoing missions lost their viability.