Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

A flooded Mexican cave that hides a river beneath the water.

A true treehouse near Hawai'i Volcanoes National Park.

The spot where the namesake of the Douglas fir met his mysterious end on a Hawaiian volcano.

The longest continuously operating Elk's Lodge in the country.

Sunset-colored dunes of volcanic ash make taking a poor photo impossible.

This interactive gallery makes you feel like you've stepped into a fantasy world filled with whimsical monsters.

A mountain range on an active U.S. Navy base hides thousands of mysterious prehistoric rock carvings.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

Ancient human, animal, and geometric figures drawn in the earth.

Smooth basaltic rocks tell a tale of ancient glacial waterfalls.

Witnessing the might of this dessert-colored desert waterfall is a rare, powerful treat.

This raised bulls-eye visible from space was the subject of an intense geologic controversy.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

The remnants of an archaeological camp stand within Tikal National Park.

Giant money stones of Yap.

The deadly but beautiful ornamental oleander was planted all over the island of Galveston after the hurricane of 1900.

This strange example of the Egyptian Revival architecture trend now holds Mardi Gras floats.

A World War II officers' club features Old West murals painted by German POWs.

This expansive bridge in the Canadian wilderness was originally just built for friends.

At just six feet two inches deep, it is said by Guiness and Ripley to be the world’s narrowest freestanding office building.

Huge otherworldly domed rocks on the shore of a deadly lake.

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