The final mission that put humans on the Moon is once again at the center of America's UFO debate after newly released Pentagon UAP files revealed a series of unexplained sightings reported by Apollo 17 astronauts during the December 1972 mission - alongside renewed claims that the crew may have received a warning from extraterrestrials to "never return.

UFOs have come to Washington again — this time, in a newly released tranche of more than 150 previously classified documents that cover nearly 80 years of alleged sightings.