Apollo was NASA's moon exploration program. In 1969 Neil Armstrong and Buzz Aldrin were the first men to walk on the moon with Apollo 11, the last Apollo mission was Apollo 17 in 1972. Apollo 18, 19 and 20 were planned missions, but due to budget constraints they were finally canceled.
Apollo 20 had already been cancelled in on January 4, 1970 as its Saturn V rocket was now needed for the Skylab space station and budget restrictions had limited the Saturn V production to the original 15 flight models.
Nevertheless, you can find a large amount of false info about Apollo 20 on the web - years ago William Rutledge, a man living in Rwanda who claimed to have been a former Bell Laboratories scientist and employed by USAF, said there was a top secret soviet-american Apollo 20 mission that found an alien spaceship on the moon.
According to the conspiracy theory Apollo 20 arrived on the moon on August 16, 1976, about four years after the last official Apollo mission. The destination was Delporte, a lunar impact crater on the Moon's far (dark) side. Crew members were William Rutledge (US), Leona Snyder (US) and Alexei Leonov (USSR), and their mission was to explore an alien spaceship apparently detected by the Apollo 15 crew (David Scott, Alfred Worden and James Irwin) in 1971.
It can at least be confirmed that Alexei Leonov was a real astronaut, he was even the first person to walk in space on March 18, 1965, and he commanded the Soviet side of the Apollo-Soyuz mission, Soyuz 19, the first joint space mission between the Soviets and the USA. In Arthur C. Clarke's "2010: Odyssey Two" the fictional spaceship "Cosmonaut Alexei Leonov" in the book was named after him. But Lenov never admitted having been part of a top secret Apollo 20 mission.
If you believe William Rutledge's story, the astronauts visited both an ancient city on the moon's surface as well as an alien spaceship. They were also able to collect some alien gadgets in the ship and brought one of the two dead alien pilots back to their Lunar Module. An analysis of meteor impact density on the city and the ship apparently revealed that both the city and the ship must been there for about 1.5 billion of years. And it seemed that the ship had already been explored before (probably by another alien race?).
William Rutledge posted videos and images on YouTube (username "retiredafb") and other websites, and the story even got some media coverage. Even if there are considerable flaws in the videos that allowed to identify the story as a hoax, one has at least to admit that they are well done and look quite amazing and that Rutledge (or who ever released this) spent some time on creating the mockups.
The story probably has its origins on a former story about photos taken during the Apollo 15 mission. These images are genuine NASA photos and can be downloaded from the Universities Space Research Association for example. Image AS15-P-9625 shows the Delporte region, which really includes a quite strange object:
It's probably nothing but an optical illusion (remember the Face on Mars?), but you'll have to admit that it looks like some kind of a cigar inside a crater, and it even seems to cast a shadow on the surface.
Jos Kirps is the creator of several software and web projects, including Galaxiki, a fictional galaxy where site members can get their own solar system and the Open Source CorneliOS webOS.