The Best Searching for Aliens Documentaries

Space & the Universe - 216 free documentaries about searching for aliens.

Start with Alien (Featuring Will Smith) (47 min, National Geographic), then What Happens If We’re Contacted By Aliens? (51 min, Spark). All 216 documentaries here are free to watch from their makers' official uploads. To read deeper, the top-rated book on searching for aliens is The Eerie Silence by Paul Davies.

• Alien (Featuring Will Smith) | Full Episode | One Strange Rock (47 min, National Geographic)
• What Happens If We’re Contacted By Aliens? (51 min, Spark)
• Is There A Simple Solution To The Fermi Paradox? (21 min, PBS Space Time)
• There Are Thousands of Alien Empires in The Milky Way (14 min, Kurzgesagt)
• Why Aliens Might Already Be On Their Way To Us (11 min, Kurzgesagt)
• Are There Lost Alien Civilizations in Our Past? (10 min, Kurzgesagt)
• Why We Should NOT Look For Aliens - The Dark Forest (11 min, Kurzgesagt)
• What Do Alien Civilizations Look Like? The Kardashev Scale (12 min, Kurzgesagt)
• We’ve Been Searching for Aliens the Wrong Way. That’s All About To Change. . . (21 min, PBS Space Time)
• What Actual Aliens Might Look Like (16 min, Kurzgesagt)
• Searching For Aliens and Our Place in the Universe | How the Universe Works (85 min, Science Channel)
• What If Alien Life Were Silicon-Based? (22 min, PBS Space Time)
• We Might Find Alien Life In 1,688 Days (18 min, Veritasium)
• Secret Pyramids Hide Beneath Earth's Surface | Ancient Aliens: Declassified (S1, E16) (166 min, HISTORY)
• How To Know If It's Aliens (19 min, PBS Space Time)
• Did Ancient Humans Draw Aliens? | Ancient Aliens (49 min, HISTORY)
• Aliens & the Power of Three Explained | Ancient Aliens (26 min, HISTORY)
• 2025’s Biggest Alien Discoveries (Part 2) | Ancient Aliens (64 min, HISTORY)
• Groundbreaking & Unexplainable Technology | Ancient Aliens (46 min, HISTORY)
• Biggest Bible Revelations | Ancient Aliens (38 min, HISTORY)
• Mysteries Hidden Under Alaskan Ice | Ancient Aliens (21 min, HISTORY)
• Discovered: Top Secret Alien Bases | Ancient Aliens (19 min, HISTORY)
• Ancient Aliens: TOP ALIEN CONSPIRACIES OF 2024 (57 min, HISTORY)
• How Will We (Most Likely) Discover Alien Life? (19 min, PBS Space Time)
• Could God Be An Alien? | Ancient Aliens (39 min, HISTORY)
• Did Aliens Leave These Artifacts Behind? | Ancient Aliens (34 min, HISTORY)
• Frozen Clues to Alien Visitors | Ancient Aliens (37 min, HISTORY)
• Underground Aliens Emerge Across the Globe (S2, E4) | Ancient Aliens (44 min, HISTORY)
• The Truth About Alien Disclosure | Ancient Aliens (24 min, HISTORY)
• Were the Ancient Gods Actually Aliens? | Ancient Aliens (37 min, HISTORY)
• The Hybrid Theory: Human or Alien? | Ancient Aliens (33 min, HISTORY)
• Did aliens build these mega structures? | Ancient Aliens: Declassified (S1, E39) (165 min, HISTORY)
• Evidence of Strange Human Hybrids Revealed | Ancient Aliens (35 min, HISTORY)
• The Moon's Mysteries Revealed | Ancient Aliens (35 min, HISTORY)
• Groundbreaking Alien Connections of India | Ancient Aliens (35 min, HISTORY)
• The Rise of Super Advanced Humans | Ancient Aliens (18 min, HISTORY)
• Aliens Invade 4 Major Cities | Ancient Aliens (19 min, HISTORY)
• SHOCKING EVIDENCE of Founding Fathers Linked to Aliens | Ancient Aliens (20 min, HISTORY)
• Secret Biblical Texts Unlocked | Ancient Aliens (21 min, HISTORY)
• Why Alien Life Would be our Doom - The Great Filter (8 min, Kurzgesagt)
• The REAL Possibility of Mapping Alien Planets! (21 min, PBS Space Time)
• Could We Decode Alien Physics? (19 min, PBS Space Time)
• 10 Hidden Alien Bases Across the Globe (S20, E3) | Ancient Aliens (42 min, HISTORY)
• Aliens Were Already Here | Ancient Aliens (22 min, HISTORY)
• Ancient Aliens: TOP UFO MYSTERIES OF 2025 | Part 1 (59 min, HISTORY)
• When Aliens Walked Among Us | Ancient Aliens (37 min, HISTORY)
• Alien Truth-Seekers Unite: Rick, Marty & Travis | Ancient Aliens (43 min, HISTORY)
• Earth's Most Inexplicable Places | Ancient Aliens (21 min, HISTORY)
• Ancient African Cultures & Their Alien Connections | Ancient Aliens (21 min, HISTORY)
• Ancient Aliens: The TRUTH Behind the Origins of Life (19 min, HISTORY)
• Ancient Aliens: Shocking Extraterrestrial Sightings in India (19 min, HISTORY)
• Ancient Aliens: Georgio’s Top Alien Breakthroughs (18 min, HISTORY)
• Ancient Aliens: Unlocking Secret Extraterrestrial Codes (19 min, HISTORY)
• Ancient Tech That's OUT OF THIS WORLD | Ancient Aliens (24 min, HISTORY)
• Aliens in Australia | Ancient Aliens (37 min, HISTORY)
• Gods & Aliens From Above | Ancient Aliens (23 min, HISTORY)
• Do These Ancient Sites Prove Alien Contact? | Ancient Aliens (40 min, HISTORY)
• Do Ancient Stories Reveal Aliens? | Ancient Aliens (25 min, HISTORY)
• Craziest Alien UFO Crashes | Ancient Aliens (36 min, HISTORY)
• Were Zeus and Thor Actually Ancient Aliens? | Ancient Aliens (23 min, HISTORY)
• Did Aliens Shape Human Civilization? | Ancient Aliens (S1, E3) (88 min, HISTORY)
• Did Aliens Build Ancient Power Plants? | Ancient Aliens (44 min, HISTORY)
• Are We Part Alien? | Ancient Aliens (25 min, HISTORY)
• See Evidence of Hawaii's Extraterrestrial Visitors | Ancient Aliens (S14, E12) (42 min, HISTORY)
• Did Aliens Predict Humanity’s End? | Ancient Aliens (30 min, HISTORY)
• Alien Horrors This Halloween | Ancient Aliens (35 min, HISTORY)
• Giorgio’s Global Search for Alien Clues | Ancient Aliens (34 min, HISTORY)
• Are the Greys Already Among Us? Alien Hybrids & Robots Revealed | Ancient Aliens (24 min, HISTORY)
• Alien Messages & Symbols: Hidden Clues from Beyond | Ancient Aliens (26 min, HISTORY)
• Voices of the Gods? Ancient Texts Reveal Alien Close Encounters | Ancient Aliens (24 min, HISTORY)
• Are Aliens Spying on the U.S.? These Sightings Might Prove It | Ancient Aliens (36 min, HISTORY)
• See the Alien Ties to Ancient Societies Across the World | Ancient Aliens (37 min, HISTORY)
• Forbidden Alien Knowledge Finally Told | Ancient Aliens (20 min, HISTORY)
• Aliens Over Asia *Insane Video Proof* | Ancient Aliens (26 min, HISTORY)
• Is The End Closer Than We Thought? | Ancient Aliens (30 min, HISTORY)
• Erich von Däniken's BIGGEST Alien Claims | Ancient Aliens (19 min, HISTORY)
• Astonishing Viking Encounters With Aliens | Ancient Aliens (21 min, HISTORY)
• Ancient Aliens: These 4 Alien Abductions Will Give You Nightmares (21 min, HISTORY)
• Out Of This World Extraterrestrials | Ancient Aliens (38 min, HISTORY)
• Alien Influence in Australia | Ancient Aliens (21 min, HISTORY)

Top-Rated Books About Searching for Aliens

1. The Eerie Silence by Paul Davies - View on Amazon
2. Extraterrestrial by Avi Loeb - View on Amazon
3. Rare Earth by Peter Douglas Ward - View on Amazon