The Apollo program was designed to land humans on the Moon and
bring them safely back to Earth. Six of the missions (Apollos
11, 12, 14, 15, 16, and 17) achieved this goal. Apollos 7 and 9
were Earth
... orbiting missions to test the Command and Lunar
Modules, and did not return lunar data. Apollos 8 and 10 tested
various components while orbiting the Moon, and returned
photography of the lunar surface. Apollo 13 did not land on the
Moon due to a malfunction, but also returned photographs. The
six missions that landed on the Moon returned a wealth of
scientific data and almost 400 kilograms of lunar
samples. Experiments included soil mechanics, meteoroids,
seismic, heat flow, lunar ranging, magnetic fields, and solar
wind experiments.
[Summary provided by NASA]