What on Earth? Season 12, Episode 9: Secrets of Biosphere 2

Bullseye in the Sky

Satellite capture a bizarre pattern obscuring an eastern Atlantic island.

42 min

Mystery of the Fallen Star

Aerial archaeologists use laser imaging to capture a distinct star-shaped pattern carved into the marsh of a Florida swamp; experts investigate and reveal a lost Civil War fort linked to an extraordinary community with a tragic past.

42 min

Indiana's War Factory

Satellite images capture a large compound of abandoned structures that are overgrown with vegetation in Indiana; experts investigate and uncover a derelict WWII munitions factory that played a crucial role in US military history.

42 min

Turkey's Lost Terror Dome

Aerial drone imaging captures a circular man-made structure that appears to be centuries-old in the remote forests of Aydin, Turkey; experts investigate a lost ancient amphitheater with a history steeped in gladiatorial bloodshed.

42 min

Blood Feud of Gresham Castle

Satellite images capture a mysterious fortification concealed beneath a patch of woodland in the remote stretches of Norfolk, England; experts investigate rival royal families and a lost castle that was destroyed during a medieval blood feud.

42 min

The Boneyard of Arizona

Satellite images capture miles of aircraft precisely arranged in the vast Arizona desert; experts investigate the largest aircraft storage facility on Earth and the rotting remains of a defining moment in Cold War history.

42 min

Nevada's Mystery Marking

Satellite images capture an enormous X shape mysteriously carved with precision in the remote Nevada desert; experts investigate a military emergency landing field linked to one of the most astonishing test programs in aviation history.

42 min

Ghost Ship of Ireland

Satellite images reveal a mysterious vessel that suddenly appears marooned on a remote stretch of Ireland's southern coast; experts investigate and uncover a bizarre journey near the Bermuda Triangle that resulted in a US Coast Guard interception.

42 min

Arctic Hunters of Norway

Aerial archaeologists capture a series of mysterious dots buried beneath the remote, frozen landscape of Finnmark, Norway; experts investigate and reveal revolutionary hunting techniques developed by the oldest surviving Norwegian tribe.