A castle that was built stone by stone by an eccentric journalist.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

See massive fossils that are over 200 million years old in northeastern Arizona.

In the remote high desert of New Mexico, a strange array of poles beckon fury from above.

A multi-storied adobe complex has been inhabited for more than a thousand years.

The 606 is a decade in the making.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

Home to drunken tower-climbing goats... seriously.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

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

A crumbling hospital from the 1850s on Roosevelt Island.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.