Go inside to really appreciate this 500-year-old technological masterpiece.

Once the home of a hermetic monk, this cave now houses a small church.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

A Texas museum filled with Broncos and Betties.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Three hundred years of preserved Spanish colonial history in San Antonio.

Where monkeys run wild and the humans are caged.

Former villa and estate of James Deering developed to preserve native tropical forests.

When you can't get to the Pacific, just go to Florida.

A tribute to Ponce de Leon's supposed quest for eternal youth.

In this case, 'zero' marks the spot where the iconic Old Spanish Trail ends.

It's a pretty creepy lock-up.

Arrr! The most authentic collection of pirate artifacts in the world... matey.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

Public works and national defense project meant to carve a canal all the way across the state of Florida.

Despite being made of a seashell mortar, the crumbling remains of this historic Florida mill are still standing.

This abandoned NASA launch site is now a memorial to a trio of astronauts who were killed there.

A building so large that it has its own weather.

This kitsch eatery is chock-a-block with bric-a-brac.