Part of one of the largest flooded cavities on the planet, and littered with prehistoric animal bones.

The Ozarks' strangest dwelling.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

The world's largest Holstein cow.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

These subterranean storage areas hold emergency water reserves.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

This stately estate house features a tower covered in a bright, modern mural.

Known as the most dangerous bridge in the world, the Hussaini Hanging Bridge is only one of many precarious rope bridges in Northern Pakistan.

The place where World War I began.

Giant granite rocks standing end-to-end like a train of circus elephants.

A Very Low Frequency transmitter you can tune in on your PC.

"The country that ate itself."

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

A gallery of underwater art that can be visited by man and fish alike.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

The curios of pharmacist and collector Henry Wellcome.

Where cemeteries are carved into the side of cliffs and infants are buried in the hollows of trees.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

Underwater volcanic eruption forms new island off the coast of Tonga.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

A toxic lake near a volcanic caldera that is home to flamingos and other life.