Aerial archaeologists capture bizarre, spider-like markings etched deep into the mountains of Northern Spain; experts investigate an ancient site that contained one of the largest and most important gold mining operations of the Roman Empire.

Aerial drone imaging captures clusters of enormous, perfectly round holes scattered along the coast of the Dead Sea in Israel; experts reveal a history of destructive water diversion linked to massive sinkholes devouring the region.

Satellite images capture a series of enormous zigzagging patterns carved into the remote woodlands of Poland; experts investigate a clandestine Nazi base linked to a doomed operation that played a pivotal role in the downfall of WWII Germany.

Aerial drone imaging captures oddly shaped industrial-sized towers mysteriously situated in a forest clearing near Moscow; experts investigate and uncover a lost Soviet-era military compound and the development of a catastrophic electromagnetic weapon.

Satellite images capture the Hill of Tara, two conjoined circular structures embedded in Ireland's lush and rolling landscape. Experts investigate the ancient site used to crown the legendary High Kings of Ireland at the Stone of Destiny and the elusive hunt for the Ark of the Covenant by the British Israelites in the 1890s.

Satellite images capture a triangular castle-like tower, a Nuraghe, located on the Mediterranean island of Sardinia; experts investigate these relics of the declining, ancient Nuragic civilization that may have suffered a celestial catastrophe.

Satellite images capture monumental ruins surrounded by bizarre feather-shaped structures on a Welsh mountaintop; experts investigate a hidden tunnel containing the remains of an abandoned slate mine with an exploitative and deadly past.

Satellite images capture bizarre structures fenced within a remote mountaintop complex on the Greek island of Kefalonia; experts investigate and discover a network of massive satellites linked to a hidden NATO doomsday communications bunker.

Satellite images capture dozens of perfectly straight parallel lines hidden in the dense Polish woodlands of Silesia. Experts investigate and uncover a massive WWII military complex once used as a notorious and deadly Nazi weapons training facility for developing the MP44 Sturmgewehr machine gun and training the 13th Waffen SS Mountain Division.

Satellite images capture a bizarre industrial complex in the remote desert expanse of Kazakhstan. Experts investigate and uncover a massive hangar containing a Buran or  Soviet space shuttle, the most expensive spacecraft in the history of Soviet-era space exploration.