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.

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

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

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

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

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 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.

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?

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

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.

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

Ghost lakes have existed for millions of years, but they just recently started showing themselves. Geophysicist Helen Fricker explains how scientists are moving forward with this discovery.

Experts investigate a river surrounded by death.

A satellite captures an image that uncovers the entrance to an underground complex. What is being built there?

A mysterious shape in the water leads people to believe a giant monster is roaming Loch Ness. Is that really what’s going on though?