Rob Nelson investigates rumors of a secret underground escape route used by the infamous gangster Al Capone. In Washington state, Rob tries to uncover who -- or what -- built a vast landscape of earthen mounds in Washington state.

Rob Nelson explores mysterious tunnels beneath Denver's airport and capitol building to investigate rumors of a secret organization operating below. In Ohio, he tries to uncover the ancient secrets of a mound shaped like a serpent.

Rob Nelson hunts for a legendary mass grave that could expose a dark secret of America's industrial past. High in the mountains, a giant lake is mysteriously disappearing, and Rob uses cutting-edge technology to find out why.

Rob Nelson examines a set of bizarre markings that suggest a violent clash between prehistoric beasts. In California, he investigates if a strange lake is a home to alien life.

Rob descends into a cave 30 feet beneath Texas in search of evidence of a mass extinction event. Then, he heads to Lake Michigan to investigate a Bermuda Triangle-like phenomenon that has caused ships to vanish for centuries.

Rob Nelson heads to California to investigate a network for major fault lines that could set off an unprecedented mega-quake. Then, he explores a mysterious sinkhole that some believe is an endless pit to the center of the Earth.

Rob investigates ancient ruins in New England that suggest Europeans arrived in the Americas almost 1,000 years before Columbus. Then, he heads to California where a dormant super-volcano may be showing new signs of life.

Rob Nelson investigates the mysterious pattern of rocks at the bottom of Lake Michigan known as Underwater Stonehenge. At the notorious Alcatraz prison, Rob uses state-of-the-art technology in search of rumored escape tunnels.

A legendary train filled with stolen Nazi gold is said to be hidden in Poland. Using cutting-edge technology, Rob Nelson and Stefan Burns explore deep underneath the earth's surface and in abandoned Nazi tunnels in search for the infamous legend.

Priceless gold and silver artifacts are believed to be in fabled lost Temple Treasures of Jerusalem & King Solomon's hidden mines. With unprecedented access, Rob Nelson and Stefan Burns use the latest technology to search for the legendary treasure.

Nikola Tesla died before finishing a mysterious, earth-shattering invention, but the ground beneath his only remaining lab might hold clues. Rob Nelson & Stefan Burns are the first to use cutting-edge tech to investigate Tesla's underground secrets.

A massive supervolcano beneath Naples, Italy may be on the verge of erupting again, which could have apocalyptic consequences across the planet. Rob Nelson and Stefan Burns use cutting-edge technology to investigate this disturbing new evidence.

New theories claim that the legendary sunken city of Atlantis could have actually been in the Americas. Rob Nelson & Stefan Burns use cutting-edge technology to investigate evidence that might shed more light on one of the world's greatest mysteries.

A strange cave freezes in the summer and melts in the winter, and a massive sand dune swallows a small child in an instant. Rob Nelson and Stefan Burns use cutting-edge technology to investigate these mysteries of the natural world.

When an infamous pirate city sunk into the sea after a massive earthquake, a pirate's treasure might have disappeared with it. Rob Nelson and Stefan Burns use cutting-edge technology to hunt for the legendary lost pirate treasure of Henry Morgan.

Millions of dollars of stolen Gold Rush treasure is rumored to have been stashed in a cave in Northern California. Rob Nelson and Stefan Burns use cutting-edge technology to search for the legendary treasure.