One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

This long, dark tunnel is open to hikers, but those without lights are known to get confused even on the straight path.

The longest spit in the United States ends at a lighthouse in the Strait of Juan de Fuca.

An abandoned World War II bunker is part of a chain that runs throughout Washington.

An impromptu shrine appeared shortly after beloved "Torchwood" character Ianto Jones was killed off the show.

Diego Rivera hid various people and symbols in his first large-scale mural project.

The castle still holds traces of the abandoned Roman fort it was built atop.

Recently restored menagerie of Victorian-era beasts.

High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.

This museum remembers an apocalyptic cult that became more famous for baseball than religious radicalism.

The remains of a religious colony, its amusement park, zoo, and baseball empire.

The strange phenomenon causing gravity to "work backwards" on this hill has been blamed on the paranormal.

Home to the deepest rift anywhere on Earth.

These falls, sometimes called the "Niagara of the West," still put on a good show at the right time of year.

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.

A unique collection of drawings that represent Fremont Native American culture.

Inside this striking glass building, visitors can see thousands of dinosaur fossils in the positions that nature deposited them more than 150 million years ago.

Devilish landscape, once cinema home to giant alien bugs, now derelict roadside attraction.

This amazingly preserved Gold Rush town is a historian's dream.

This giant meditative chakra sits peacefully in the Flathead Valley of western Montana.

People come from across the globe to swim in this lake believed to have healing properties.

An exercise in patience and imagination, where Mother Earth turned common stuff into precious hidden treasures.

What is the Thing?

The fading, forgotten remains of a once bright and booming factory.