One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

Civil War Fort on an island in the Boston Harbor.

This foolish Victorian sea fort was converted to a deluxe hotel.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

New fungal and bacterial species call this deadly lake home.

A mud volcano in Indonesia spews out 50,000 cubic meters of mud every day.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

A small flooded ghost town with a few scattered structures remaining.

A toxic ghost town sitting atop a massive coal fire.

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

A beautiful geyser under environmental threat.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Stay in the one time home to one of Scotland's most notorious gentleman's sex clubs.

Unique geological formations in China, featuring some suggestive shapes.

An exquisite tunnel of cascading flowers.