America's Swamp Castle: Satellite images capture bizarre structures in the remote and inhospitable swamplands of Louisiana; experts investigate a forgotten war-torn fortress with a mysterious connection to the sinking ruins of a classified military installation.
Airdate: Thurs 8 Apr 2021 at 22:00 on Science
Season 9 Episode 5
What on Earth? is a documentary series using satellite images of strange geological occurrences and man-made structures on Earth to examine such matters as the planet's extreme locations, phenomena and species.