A perfectly circular lake is formed by the crater of an ancient underwater volcano.

"We Seceded Where Others Failed."

Near the ruins of a Civil War coastal fortress lies the only known African refugee cemetery in the United States.

A historic presidential getaway on the continental United States' southernmost island.

A monument celebrating the idea of reaching inaccessible places.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

An artsy hidden staircase leads to breathtaking views of San Francisco.

Millions of years of oxidation make a drive down this winding Death Valley road surprisingly colorful.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

Years of neglect and nature took a toll on this 19th-century lighthouse.

Rusting, graffiti-covered tanks litter the beach of this island, once used by the U.S. military for target practice.

Invading U.S. troops were first seen from this now-abandoned tower, leading to the Spanish-American War.

Legend has it this historic port was a popular hideout and smuggling spot for pirates.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This abandoned five-star hotel is now a five-star urban exploration destination.

This fairy-tale, neo-Gothic church in the Azores is a world of magical realism.

This chapel on a cliff is renowned for its healing powers and was founded on the site of a supposed divine intervention.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

This tiny home was originally a narrow alleyway.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

A Montreal deli that was so beloved that it was allowed to circumvent their laws of language.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.