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

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

One of the only memorials dedicated to journalists who died in combat.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

This one-room cabin where the young colonel slept during the French and Indian War.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

The prototype for all Nazi concentration camps.

An underground city of salt.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

Underneath the city that invented pilsners are a series of historic tunnels that have been storing beer for centuries.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

Catacombs turned marketplace.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

A community of artists and entrepreneurs seeks a simpler life on London's waterways.

A museum in England’s Lake District dedicated to the trusty pencil wants you to know the story of their World War II spy pencils.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

Swiss vineyards in a UNESCO heritage site.

The most powerful waterfall in all of Europe.