Tropical paradise strewn with hundreds of World War II wrecks.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.

A war relic that has sat undisturbed since it crash-landed near Arno Atoll.

An enormous concrete structure built over a nuclear crater.

A desperate final message left by a POW on the run serves as a memorial for himself and the 97 that died with him.

An abandoned guano-mining city in the South Pacific.

Abandoned outpost once home to a murderous tyrant.

This dramatic sea spire is home to the world's rarest insect and is part of the lost continent of Zealandia.

A true treehouse near Hawai'i Volcanoes National Park.

A model of a galactic embassy is hidden in plain sight along the highway, proposed by a UFO religion to find the aliens that created life on Earth.

Get up close and personal with these majestic fish.

Hide from the tourist hordes in these relatively unknown, and unguarded lava caves.

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

A beach made of semi-precious green sand on the Big Island of Hawai'i.

Mai Tais and Navy Grog served up in one of the original tiki bars.

The world's longest known cave system.

Statue dedicated to the star of an old television show.

This quirky museum has a collection of more than 15,000 bobblehead dolls.

The oldest certified bowling alley in the United States is in the basement of this century-old bar.

This shallow pit was once used to send over 20,000 buffalo plummeting to their death.

Two massive and unstable sinkholes are yearning to unite, and their consummation could be catastrophic.

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

A museum dedicated to the alleged Roswell Incident.

Home of the International Space Hall of Fame.