On 19th of November 1969 Charles Conrad and Alan Bean become the 3rd and 4th humans on the Moon.

Crew

Charles Conrad Jr., Commander
Alan L. Bean, Lunar Module Pilot
Richard F. Gordon Jr., Command Module Pilot

The primary mission objectives of the second crewed lunar landing included an extensive series of lunar exploration tasks by the lunar module, or LM, crew, as well as the deployment of the Apollo Lunar Surface Experiments Package, or ALSEP, which was to be left on the moon’s surface to gather seismic, scientific and engineering data throughout a long period of time.

The astronauts also were to retrieve portions of the Surveyor III spacecraft, which had soft-landed on the moon April 20, 1967, a short distance from the selected landing site of Apollo 12.

Click this link for more on Apollo 12: Apollo 12: The Pinpoint Mission