Ancient Aliens: Crystal City Discovered Under Antarctica (Season 18) | History HISTORY September 12, 2022 Leave a Comment on Ancient Aliens: Crystal City Discovered Under Antarctica (Season 18) | History Posted in Seen Them Share: XFacebookPinterestLinkedin During an Arctic expedition, naval officer Richard Byrd makes a very unusual discovery, in this clip from Season 18, “Secrets of … source Author: HISTORY