Berlin's old airport.

The prototype for all Nazi concentration camps.

Floating swimming pool within a moored vessel.

Super-heavy Nazi architectural experiment.

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

Started as a kitchen garden, now the second largest botanical garden in the world.

The fairy tale castle of the "fairy-tale king."

A simple plaque on the facade is the only reminder that the treaty ending the American Revolution was signed inside.

This demon atop the Notre-Dame de Paris looks utterly bored.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

A 400-year-old church covered floor to ceiling in ex-voto offerings from the faithful.

The Argonaute submarine was the French navy's pride and joy in the 1950's.

This bridge was constructed from the rubble of the infamous Bastille.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

An icy lake tucked among jaw-dropping alpine panoramas.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

Hundreds of hidden passageways weave through the old quarters of Lyon.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

France's most famous cemetery, with some of its most curious tombs.

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

The beautiful baroque library of the Hapsburg empire.

A small museum in the Bay of Pigs gives the Cuban perspective on the famously failed U.S. invasion.