What on Earth? Season 4

Strange mounds in Transylvania might pinpoint the location of the tomb of the bloodthirsty tyrant believed to have inspired Dracula. A mysterious ancient city is discovered on a coral reef. Images of a plane crash sets off a hunt for a drug lord.

A strange structure shaped like a giant shark might point the way to a lost civilization's Fountain of Youth. A massive hurricane heads toward Florida but something unexpected is in its eye. Bizarre marks across the eastern US leave experts baffled.

A ghost ship with links to the mob suddenly appears on a California beach; strange markings could be a coded message that reveals a plot to overthrow the Queen of England; a lake believed to have magical healing powers holds clues to life on Mars.

A ghost town covered in a strange, white power emerges from a lake in Argentina; upon the discovery of a lost jungle in Africa, scientists embark on a dangerous mission to explore it; a declassified CIA image uncovers a bizarre, giant Soviet weapon.

A strange forest of razor-shape stones could be home to an undiscovered Hobbit-like humanoid species; when a man-made island mysteriously appears off the US coast, new evidence points to secret government experiments into psycho-chemical warfare.

A forbidden island points to a strange South American town that locals claim was the home of Adolf Hitler. New data from NASA satellites might reveal a sunken lost continent in the Indian Ocean. A pit of bodies suggests fears of a zombie nightmare.

A strange lake in Transylvania is the home of an abandoned village and a terrifying secret. When an labyrinth is discovered on an island once home to an ancient Greek civilization, experts investigate if it was the legendary home of the Minotaur.

A lost city near Jerusalem might have been the home of Goliath; bizarre underwater formations might point to a top-secret US weapons testing facility; a strange sighting in the Arctic could be a lost Nazi relic.

An abandoned megacity in a remote jungle might be the home of an ancient treasure and a dark secret; when a mysterious circular stone structure is discovered in Scotland, experts investigate whether it's the fabled Round Table of King Arthur.

Evidence of human sacrifice for the Viking god Odin; shedding new light on Genghis Khan.

New evidence might finally identify the hiding place of the billion-dollar Nazi gold train; a discovery of a long-lost settlement rewrites the history of the Vikings in North America; a blood-red river in Siberia points to catastrophic pollution.

An ancient man-made volcano might reveal buried treasure and bloody human sacrifice. When NASA discovers a strange pattern in the Arctic ice, experts investigate if it has alien origins. A mystery in the Sahara might have a sinister explanation.

Man-made islands are spotted near a North Korean missile facility. When something unexpected is found in a remote desert, experts investigate a lost city of giants. A strange discovery in Siberia could reveal a mission to the center of the earth.

An abandoned city in the African jungle might have a bloody past of malevolent spirits and cannibals. Mount Vesuvius shows signs that it's awakening, and the mafia could be to blame. Experts investigate Hitler's secret Nazi UFO program.

Experts investigate a glowing lake reported to turn things into stone. A mysterious structure in Africa that resembles Stonehenge is said to be the resting place of a mythical giant. A dark conspiracy could be at work in the Australian outback.

A mysterious Stonehenge-like structure in Russia might have links to the Nazis. Experts uncover clues to a mega-tsunami with the power to devastate the United States. A huge lake appears in the Sahara overnight, and its explanation could be mythical.

New discoveries lead investigators to a crypt rumored to hold the Ark of the Covenant. When great white shark is killed, experts suspect an mysterious ocean monster. Strange markings in the desert might be a tribute to an ancient spider god.

Treasure hunters have searched for a lost Incan city of untold wealth for a century, but new technology might finally locate its riches; a strange mountain in Egypt sparks an investigation into Cleopatra's gems and the tomb of Alexander the Great.

A ghost ship is found abandoned on a remote island that's home to one of the world's last uncontacted tribes. A strange labyrinth in Sicily might have a sinister connection to the Mafia. New evidence reveals a mysterious military compound in Russia.

New evidence might reveal how the Mayans vanished; when scientists investigate an abandoned settlement, they discover traces of ritualistic drug binges from the ancient world; a mysterious symbol in the desert points to a sex cult of millionaires.