What on Earth?

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 aviation history's most astonishing test programs, the X-15. It flew over six times the speed of sound and at altitudes over 62 miles high.

A ghost ship appears overnight on the shores of Ireland after a powerful Atlantic cyclone named Storm Dennis in February 2020. The MV Alta was abandoned at sea in October 2018, southeast of the Bermuda Triangle. Could it help shed light on the fate of vessels claimed by the most notorious patch of ocean on Earth? Could its 17-month drift help scientists better understand complex ocean currents?

Satellite images capture a mysterious group of pyramid-shaped structures in Arizona's arid, desert landscape. Experts investigate Biosphere 2, a highly controversial research facility designed to prepare humanity for life on another world.

Aerial archaeologists capture a series of mysterious dots buried beneath the remote, frozen landscape of Finnmark, Norway. Experts investigate and reveal revolutionary reindeer hunting techniques using trapping pits developed by the Sámi, the oldest surviving indigenous Norwegian tribe.