A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

This star-shaped military outpost is now simply trying to protect itself from neglect.

Nine limestone rock stacks on Australia's "Shipwreck Coast."

Across the Pacific in a raft, a museum dedicated to Thor Heyerdahl's now legendary expedition.

Abandoned 19th century homes once occupied by naval officers, soon to be demolished.

A replica viking ship from the Chicago World's Fair is still in dry dock in an Illinois park.

A submerged archeological park still holds the wonders of a Roman Sodom.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

Every equinox this Maya pyramid puts on a spooky ancient light show.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

An underground city of ancient quarry tunnels hid thousands of Allied soldiers in WWI.

This floating garden in the sky is straight out of a fairy tale, but the real thing is nothing short of magical.

The rusting remains of the largest assembled WWII fleet on the West Coast.

Detroit’s downtown castle is one of the oldest structures in the city.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

A fairy tale castle in modern Rome.

This foolish Victorian sea fort was converted to a deluxe hotel.

Hauled from the water's depths, Henry VIII's flagship is preserved in this capsule-shaped museum.

Giant art made in Japanese rice fields.

A world-class observatory in the California desert.

Visit the monolithic tomb of America's most famous general.

A glowing underwater cliff attracts marine life and divers in equal measure.