View the ancient remains of buildings and the ancient "River of Hades" before hopping on a train.

Burial site of the notorious Chicago gangster.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

This historic patch of real estate offers a glimpse of colonial Boston.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The headless bodies of more than 1,300 guillotined victims of the Reign of Terror are buried here in mass graves.

If you fly into Edinburgh Airport, it's possible to spot this prehistoric site without even getting off the plane.

This was once a hall in which a 16th-century royal banquet was hosted by King James VI of Scotland.

This 16th-century close preserves an unusual piece of Edinburgh's transportation history.

These steps offer a breathtaking view of one of Europe's most besieged fortresses.

This cannonball embedded in the side of an Edinburgh house once served a surprisingly pedestrian purpose.

The fountain marks the area where hundreds of accused witches were burned at the stake.

An overlooked memorial honoring the local Washington residents who died in World War I.

A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.

In 2004, a Dave Matthews Band tour bus dumped 800 pounds of waste off a bridge and onto an unsuspecting tour boat below.

Overlooking the burial ground is a tower designed to prevent thieves from snatching the recently deceased.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

The final resting place of soldiers' loyal canine companions.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

Experience life in one of America’s smallest neighborhoods.

These ancient ruins hide in plain sight next to a dessert shop.

This Ottoman-era church is hidden amid a busy tourist area.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.