This small condiment museum makes all manner of mustards with a 200-year-old mill.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This modest marker near Notre Dame identifies the very center of Paris.

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

Abandoned railway line circling the city of Paris.

A miniature city, once ruled by the Queen of the Netherlands.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

The metal leaves on this tree are engraved with the names of Holocaust victims.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

Budapest's Communist-era statues, banished to the suburbs.

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

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

This strange statue features a bust of the famous composer plopped atop a woman's body.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

The medieval network of canals hidden underneath the city is opened to explorers each year.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

An exquisite Baroque church in Vienna's old town.

The solemn exterior conceals an opulent interior of this 17th century church.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.