a means of denying Native Americans an ancestral claim on their land". Fringe theories A subculture of enthusiasts studies purported structures on the Moon or Mars. These controversial "structures" (such as the Face on Mars) are not accepted as more than natural features by most scientists, examples of the pareidolia phenomenon. Palaeocontact or ancient astronaut theories, espoused by Erich von Däniken and others, are further examples of fringe theories. These claim that the Earth was visited in prehistoric times by extraterrestrial beings. Science fiction Xenoarchaeological themes are common in science fiction. Works about the exploration of enigmatic extraterrestrial artifacts have been satirically categorized as Big Dumb Object stories. Some of the more prominent examples of xenoarchaeological fiction include Arthur C. Clarke's novel Rendezvous with Rama, H. Beam Piper's short story Omnilingual, and Charles Sheffield's Heritage Universe series. Novels 2001: A Space Odyssey by Arthur C. Clarke Broken Angels by Richard Morgan Gateway by Fred Pohl Grass by Sheri S. Tepper Heritage Trilogy by Ian Douglas Noon Universe by Strugatsky brothers. Rendezvous With Rama by Arthur C. Clarke Revelation Space by Alastair Reynolds Ringworld (and its sequels) by Larry Niven Saga of Seven Suns (Most notably Book 1: Hidden Empire) by Kevin J. Anderson Strata by Terry Pratchett The Engines of God by Jack McDevitt The Gaea Trilogy by John Varley The Giants series by James P. Hogan The Hercules Text by Jack McDevitt The novels in the Heritage Universe by Charles Sheffield The Past of Forever (Children of the Stars, Book 4) by Juanita Coulson The Season of Passage by Christopher Pike The Voyage of the Space Beagle by A. E. van Vogt Short stories "At the Mountains of Madness" by H. P. Lovecraft "Old Testament" by Jerome Bixby "Omnilingual" by H. Beam Piper "The Sentinel" by Arthur C. Clarke "The Vaults of Yoh-Vombis" by Clark Ashton Smith "The Adventure of Tintin: Flight 714 to Sydney" by Herge Video games Alien Legacy Aliens versus Predator Aliens vs. Predator Borderlands Civilization: Call to Power Dead Space Doom 3 Freelancer FreeSpace Gateway Halo series Marathon 2: Durandal Mass Effect Master of Orion Metal Fatigue Outer Wilds RAMA (based on Clarke's novel) Resistance Sid Meier's Alpha Centauri Star Trek: A Final Unity Star Wars: Knights of the Old Republic StarCraft series Stellaris The Dig The Lacuna Expanse Wing Commander: Privateer Movies A Genesis Found Alien Alien vs. Predator Alien: Covenant Black Mountain Side