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

The most visited, and possibly most controversial, museum in Germany.

Perhaps the most scandalous statue of America's first president.

The walls of the iconic dome are hollow and have a secret stairway.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

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

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

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

Two stone columns flank the grand Venice square, but there were supposed to be three.

Go inside to really appreciate this 500-year-old technological masterpiece.