A common entry point to the Griffith Observatory trail holds its own wonders.

The small cliffside monastery known as the Tiger's Nest is said to be the meditation site of an 8th-century Buddhist master.

Miraculous vase predicts the future at this Tibetan Buddhist site in the Himalayas.

A deserted hodgepodge of experimental structures designed by nearby university students.

This unique historical monument features large concrete spheres designed to resemble fallen stars.

A big museum full of little worlds.

A haunting army of decomposing, moss-covered stuffed animals and dolls guard this swinging truss.

A rotating cast of guys and dolls in front of a Washington, D.C. building.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

A massive cave complex boasts some of the clearest water (and most charming bats) in the world.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

This network of tunnels housed an entire village for years, and even had a hall for screening movies.

A Texas cave network is home to some of the world's most spectacular-looking and bizarrely named mineral formations.

Walk through the history of American pop culture.

George Washington's dentures and Queen Victoria's dental instruments are in the nation’s official museum of the dental profession.

This historic oak tree has been around for over 300 years and might last for 300 more so long as it doesn't fall apart first.

The ruins of a creative scholar's fantastical unfinished sanctuary act as his massive gravestone.

This 15-foot former Johnny Appleseed has given up his apples for donuts and coffee.

This protected reserve is home to a rare and beautiful species of flower.

The luxurious circular mansion built for a Communist leader now lies abandoned.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

Though technically an illegal structure, this eclectic DIY apartment complex is beloved by its residents.

A beautifully detailed Victorian house designed to be easy to flee, built by a man haunted by fire.