Survivors who worked at nearby factory report production areas they weren’t allowed to visit. Philip visits and finds the basement full of lab after lab of gas masks, radioactive testing materials and sand.

Philip Grossman goes inside the plant near the massive radio tower he finds maps of the U.S and pictures of mushroom clouds. Was the Duga for protecting Chernobyl from incoming missiles or part of a nuclear offensive?

Philip Grossman finds firefighting gear under a hospital in Chernobyl, sending his Geiger counter climbing. He believes burying the gear was the Soviet’s attempt to hide the scope of the disaster.

This romantic road carved into a sheer rock face in the Rhone Valley in France was an engineering marvel that was once a wild success. What caused it to be abandoned today?

Located in California, Plank Road is one of the most extraordinary engineering achievements of the early 20th century.

In the east China sea, there is an abandoned piece of land. Check out why this island represents one of the greatest engineering achievements of the 20th century.

Explore the mystery behind why a huge gun was built and abandoned.

Two miles inside a mountain in Croatia lies the remains of a massive, secret Cold War airbase built to withstand a nuclear war.

Hidden in woods outside Moscow is a Cold War weapon that harnessed electricity into a thunderbolt, designed to protect the city.

Built in the 1940’s the Goat Canyon Trestle Bridge was the tallest wooden railway system in the world.

Now abandoned, this machine once could scan thousands of kilometers.

Philip Grossman finds firefighting gear under a hospital in Chernobyl, sending his Geiger counter climbing. He believes burying the gear was the Soviet’s attempt to hide the scope of the disaster.

Philip Grossman goes inside the plant near the massive radio tower he finds maps of the U.S and pictures of mushroom clouds. Was the Duga for protecting Chernobyl from incoming missiles or part of a nuclear offensive?

Survivors who worked at nearby factory report production areas they weren’t allowed to visit. Philip visits and finds the basement full of lab after lab of gas masks, radioactive testing materials and sand.

These Transylvanian burial mounds may be the resting place of Vlad Dracula, "The Impaler."

What could be the cause of this excessive gravitational pull? A volcano, or perhaps something else?

Satellite images reveal enormous spirals in Peru. Some researchers say they are too perfect and too huge to be man made.

Remains of an ancient city, rumored to be haunted, litter the pacific island of Pohnpei.

When a perfect triangle is found in the middle of a unpopulated portion of Australia, experts begin to wonder whether or not the design is man made.

Satellite images reveal a strange hole in Antarctica. After scientists rule out whirlpools and sinkholes, they have to look back in time to find the answer.

When the Quickbird Earth Observation Satellite spots an entire fleet of abandoned boats in the middle of the desert, researchers attempt to come up with an explanation.

Satellite photos show a strange circle beneath the ice of an ancient lake. Further analysis shows that these mysterious rings appear each year. What are they?

A commercial satellite imager spots something strange in the middle of a vast desert. It looks like an airport runway, but there are no planes. No government claims ownership of this strange place.

The search for Nazi treasure leads to a secret underground bunker.

An image taken by GOME shows a strange, pulsing force spreading across North America. What on Earth is it?

Scientists are baffled when a seemingly huge tsunami headed straight for Hong Kong suddenly disappears in the water.

Experts investigate a river surrounded by death.