Plot your trip through the city on the sidewalk.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

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

A collaborative art project that transformed a neighborhood in NYC's Queens.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Harlem park dedicated to compulsive hoarders killed by their own junk.

Visit the monolithic tomb of America's most famous general.

For over 30 years the walls of this Harlem schoolyard have been a gallery of street art by "Kings and better."

12,000 sq. ft. museum tracing erotic art from antiquity to modern times.

A significant example of Czech cubist architecture—a style you won't find anywhere else in the world.

The place where Dvořák composed some of his most famous works.

A former top secret nuclear fallout shelter now operates like a hotel stuck in the Cold War.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

A slice of central Asia in the middle of Berlin.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

A museum in the building where Nazi Germany signed its surrender tells the story of World War II from the Soviet perspective.

An eerie, derelict amusement park in Berlin.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

From toys to kettles to scientific instruments, this German museum celebrates the beauty of 20th century design.

Residents of Berlin take their coffee and cake in one of the city’s most restful spaces: a cemetery.

Berlin's old airport.

Fall down the rabbit hole into a surreal journey of human consciousness "from ass to soul."