Once one of the largest producers of pig iron in the world.

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

100 year tradition of fist fights, marked by marble footsteps.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Ancient snack bar of the Roman Empire re-opened.

This Mediterranean castle was built for a millionaire and his giant dog.

New Orleans' famous cemetery, located on the site of a former race track.

A mini Wrigley Field for mini baseball players.

A 56-foot tall statue of the god of fire looks out over Birmingham, Alabama.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

These pretty kitties killed and ate as many as 135 railway workers.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Try not to get slimed in Tribeca.

Avoid gangster interaction while window-shopping.

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

A building so large that it has its own weather.

At 207 feet, one of the world's longest continuous escalators.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Exact replica of the ancient monument, but much, much lighter.

World's largest barrel containing an inn.

The world's longest known cave system.

This replica of the Greek structure is in the heart of Nashville.