How many Apollo missions landed on the Moon?

Between July 1969 and December 1972, six crewed missions descended to the Moon: Apollo 11, 12, 14, 15, 16, and 17. The profile was always the same: three crew members left Earth, two moved into the lunar module for the descent, and the third stayed in the command module in orbit, ready for docking after ascent. That arrangement explains why, with six landings, twelve people ended up walking on the surface.

The program's numbering is confusing because not every flight was meant to land. Several missions traveled to the Moon as a test, without descending, to check navigation, communications, and spacecraft behavior in the lunar environment. And there was a different case: Apollo 13 was supposed to land, suffered a serious failure in the service module on the way to the Moon, canceled the descent, and used the lunar module itself as a lifeboat. Its crew circled the Moon without landing and returned to Earth.

The six crews that did land brought back regolith and rock samples, installed instruments that kept transmitting after they left, and, on the last three missions, traveled with an electric rover that extended their exploration range. The first of those landings was Apollo 11's, on July 20, 1969, at 20:17:40 UTC in the Sea of Tranquility; the last was Apollo 17's in the Taurus-Littrow valley, on December 11, 1972. No crewed mission has touched the lunar surface since.