An abandoned saucer-shaped monument in the Bulgarian mountains.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

What might be the largest completely Jewish town in the world outside of Israel now faces dwindling numbers and empty streets.

Medicinal spa created with the discharge from a geothermal energy plant.

A plaque marks the site directly below the mid-air detonation of the atomic bomb over Hiroshima.

A look into the Church of Scientology's deeply unfavorable view of psychiatry.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

On stormy days debris from this unfinished and abandoned skyscraper rains down on the Bangkok streets.

Only two of these trees remain in the natural world, found high in the cloud forest of the island of Mauritius.

Numerous sculptures set along hiking trails symbolize and idealize the relationship between man and nature.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

The sign at the garden gate reads: "These Plants Can Kill."

This peculiar lake of pitch is so thick and viscous that one can walk on its surface.

A mysterious monument meant to be a guide into "an Age of Reason" was destroyed after an apparent bombing.

Abandoned castle was once a grand example of Russian privilege, built exclusively to win a frivolous bet between noblemen.

This deceptively salty lake looks like blushing pink lemonade.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

A beautiful maze marks where three countries meet.

Unexplained bald patches in the landscape grow and recede over time, as though they are somehow alive.

Swarms of dainty flying insects swarm into the Petaloudes Valley to get busy.

Half of a waterfall goes into the river while the other half seems to disappear.

“You better take care of me Lord, if you don't you're gonna have me on your hands.” ― Hunter S. Thompson, Fear and Loathing in Las Vegas.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.