Apollo 15:the 4-billion-year-old Moon rock, nicknamed the "Genesis Rock" #OTD in 1971.

Apollo 15 crewmembers Dave Scott (left) and Jim Irwin discovered a 4-billion-year-old Moon rock, nicknamed the "Genesis Rock" #OTD in 1971. Apollo 15 was the first mission with the Lunar Roving Vehicle, allowing astronauts to explore greater distances. pic.twitter.com/byMJECPBPZ

— NASA History Office (@NASAhistory) August 1, 2018