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

This classic restaurant features a gorgeous mirror-clad room.

A surreal museum of extraordinary industrial objects.

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

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

A hip bar decorated with walls of golden skulls.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

From scholastic to sepulchral - now under reconstruction.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

A hands-on traveling collection of the innovative devices of yesteryear.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

Elevated freight railway turned wildly successful urban park.

A reminder to choose water over wine since 1888.

This semi-hidden Manhattan restaurant is based out of a loading dock.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

One of the last few places in Manhattan that employed a pneumatic systemic keeps it on display.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

A terrific purveyor of natural history objects and curios.