The summer tourists on these cliffs are thousands of seabirds.

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

This lake in the Cascades lives up to its name, disappearing down a hole every spring.

A seemingly desolate park that belongs to two countries actually supports all kinds of wildlife.

The two massive guns that defended Cartagena Bay.

One of America's first planned communities is preserved in a state park.

A fairytale-like medieval church perched atop a rocky cliff on Italy's "Coast of the Gods."

The rustic think-space of famed naturalist John Burroughs stands exactly as he left it.

A winding, blood-red tunnel of hardened lava navigable by foot.

The former home of a railway legend and the site of a gigantic labyrinth.

This quaint museum tells about more than just the birth of Jesus: "betlémy" are an important piece of Czech history.

A display of magnificent stained glass windows is the first exhibit of its kind.

Certain traditions prevail on the least-visited island of the Aran Islands.

The shell of a medieval fortress offers commanding views of the area it once protected.

The NASA scientists behind Apollo 11 started out developing Nazi weapons at this abandoned German rocket factory.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

Blackfoot petroglyphs of southern Alberta which date back as far as 7000 B.C.

Historic site where Native American hunters once trapped and killed buffalo.

Hoodoos, naturally eroded land formations, stand 20 feet tall in the Canadian badlands.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

This sandstone gorge in New York State's Adirondack Mountains is home to waterfalls, flumes, and more.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

Historic home to one of the most famous women pioneers of the 19th century.