The skeletal frame of a decommissioned gas-pumping station offers breathtaking views of greater Berlin.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

A pub that is literally in the middle of nowhere, but continues to do business.

A history of heat is on display at this unique Austrian museum.

Physicist’s epitaph provides final confirmation to a career of turmoil.

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

A spherical "micro-nation" in the heart of Vienna.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

The beautiful baroque library of the Hapsburg empire.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

The oldest private art gallery in all of Hungary.

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

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

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

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

This bar and museum are devoted to the controversial comic book work of Kája Saudek.

Looming communist pillar with a Czech twist.

An Orwellian sculpture with eyeball cameras watches passersby.

What looks like a crashed Zeppelin is actually a bright, airy reading room perched atop a modern museum.