On February 3, 1966, the first spacecraft landed successfully - and in one piece - on the moon.
It was the first man-made object to survive landing on a planetary body other than Earth, slowing its descent with a landing bag.
After the 220lb sphere landed on the lunar surface, metal 'petals' on top opened, and the vehicle transmitted photos back to Earth from the moon.
It's one of the less well-known anniversaries of the space race - at least in the West.
The vehicle, Luna 9, was Soviet - hence the video trumpeting the achievement is in Russian.
"The Russians have made the first controlled landing of a spacecraft on the Moon. Luna 9 made its "soft" landing at 2145 Moscow time (1845 GMT)," said the BBC at the time.
"The probe immediately began taking pictures of its surroundings. It is the first time the Moon has been observed at surface level. The area viewed was to the west of the craters of Reiner and Marius in the Ocean of Storms."
"The Soviet Union has not so far released any of the photographs to the wider world."
It was one of 22 unmanned Luna probes launched by the USSR. In 1959, Luna 2 crash-landed on the moon's surface.
In 1970, Luna 16 - another unmanned probe - returned soil samples from the surface to Earth.
Luna 9's radio transmissions were picked up by Britain's Jodrell Bank observatory.
Finding that the transmissions were in a format commonly used to transmit news photographs, they were decoded by staff from the Daily Express, and sent around the world.