An underwater city for the dead.

Stay in a room with a view... of the bottom of the ocean.

A massive underwater sinkhole made famous by Jacques Cousteau.

Submerged trees jut ghost-like out of an idyllic turquoise mountain lake.

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.

Nature took her revenge on the "Wickedest City in the World."

A pixel art killer whale is frozen mid-leap in this Vancouver square.

A 19th-century Gothic, castle-like statehouse by the Mississippi River.

This sculpture garden in Death Valley makes you feel like you've slipped into some alternate reality.

A largely forgotten and touching neoclassical marble fountain overlooking a bear mound effigy.

Life-size bronzes of the Grinch, Cat in the Hat, Yertle the Turtle, Sam-I-Am, and the Lorax—and the author himself.

Built to ward off Napoleon's army, this city-sized abandoned Russian fort is now perfect for urban exploration.

The pop art icon's gravesite is broadcast 24 hours a day on his museum's website.

Now isolated, this church was once the center of a bustling village that succumbed to the Black Death.

Two old windmills got a new life as oversized sculptures of a man and a woman.

A peg-legged tightrope walker did not reveal his name as he was dying, and so he was buried as “Rope Walker."

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

One of the oldest of its kind.

Once America's tallest structure, now a Baltimore landmark.

The "last holdout of the Confederacy” actually sat at the edge of the Canadian border.

This tiny Minnesota city tried to secede from the Union as a last-ditch effort to fix its crumbling water system.

The only land territory disputed between the U.S. and Canada.

The final resting place of Captain William Becknell, the Old West frontiersman who forged the Santa Fe Trail.