The second-highest train station in Europe.

A historic observatory precariously perched at the "Top of Europe."

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

This historic Union Pacific Railroad depot is a stunning symbol of American post-Civil War progress.

This proud Teutonic warrior rises out of a German forest heralding a victory and measuring lightning.

A winged-helmed, sword-brandishing tribute to German Americans.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Possibly the oldest of Britain's ancient henges is also one of its most stark.

Scotland's only funicular railway is also the United Kingdom's highest.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

A Jenga-style cylindrical tower of books that appears to go on forever.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

If you visit the burial place of King Frederick the Great, you'll likely find a couple of potatoes sitting on his tombstone.

Elaborate hand-carved wooden clocks two brothers made in their spare time are on display at this handsome little museum.

A gorgeous medieval library where the books are kept in chains.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

This striking public art installation is suspended above a public park, designed to gently move in the breeze.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

Where the lovelorn find a home for their sentimental keepsakes.

A whimsical bridge adorned with decorative dragons.