A true treehouse near Hawai'i Volcanoes National Park.

The southernmost point in the United States is a beautiful place to look at but a deadly place to wade in.

A series of waterfalls and pools that flow through the 'Ohe'o Gulch and into the ocean.

Watch the newest land on the planet form before your eyes.

These ancient sacred grounds granted amnesty to those who managed to reach them.

A controversial memorial at the place where Captain Cook met his violent end.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

The rocks in this arid basin leave trails of movement behind them.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

This Peruvian canyon is filled with geometric salt pools that have been being harvested since the Incan empire.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

The newsstand that never closes its doors—well, almost never.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

A nuclear power plant abandoned along with an international allegience.

An eatery for UFO seekers on the Extraterrestrial Highway.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Cathedral carved out of salt, located a mile below the Earth's surface.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This nearly endless university hallway is home to a unique sunset known as "MIThenge."

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.