Ancient

4 full episodes that A&E Television Networks, LLC posts free on HISTORY, its own YouTube channel, in the order their own titles number them. Each plays in YouTube's player, with YouTube's ads, loaded only when you press Play on its page.

Start with the first episode

Season 1

  1. Earth’s Alien Energy Grid? | Ancient Aliens (S1, E8) | Full Episode Full episode · Posted 2026 · 1 h 24 min Free with YouTube's ads, posted by HISTORY
  2. Mass Production Before Machines | Ancient Impossible (S1, E8) | Full Episode Full episode · Posted 2026 · 42 min Free with YouTube's ads, posted by HISTORY

Season 20

  1. Did Aliens Guide Civilization? | Ancient Aliens (S20, E16) | Full Episode Full episode · Posted 2026 · 42 min Free with YouTube's ads, posted by HISTORY
  2. Linda Moulton Explains Extraterrestrials | Ancient Aliens (S20, E18) | Full Episode Full episode · Posted 2026 · 42 min Free with YouTube's ads, posted by HISTORY

Compilations, marathons and "best of"

Each as its own title calls it. They gather several episodes or parts of them, so they are not numbered with the episodes.