This ancient monastery complex was transformed from an island to a peninsula when the lake was partially drained.

The most visited pilgrimage site in Armenia once held a saint in a pit for 13 years.

A geological oddity topped with a 2,000-year-old pagan temple.

Apartment complexes built into huge repurposed natural gas tanks.

The world's tallest statue of an American hero.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

The oldest bar in Missouri is hidden within a limestone brewery cellar more than 50 feet underground.

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

The prototype for all Nazi concentration camps.

Dedicated to a synagogue that was destroyed after having survived World War II.

An ode to a soldier who came to town, fell in love, then began making his own sparkling wine.

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

Along the edge of this fountain are 365 smaller fountains that represent the days of the year.

Designed as a reminder of one of the darkest moments in Austrian history.

In the middle of a Vienna square, Roman ruins dating back some 2,000 years are on display.

Visiting this café is like visiting the Austrian grandma you wish you had.

A patriotic medieval knight in driven-nail armor raised money for widows and orphans of WWI.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

Museum devoted to the artificial language of Esperanto.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

The Habsburgs' royal collections of art and wonders.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.