A 12th-century fortress containing some of Berlin's oldest buildings.

A wunderkammer of mysterious objects and stories.

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

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

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

A slice of central Asia in the middle of Berlin.

An eerie, derelict amusement park in Berlin.

Chicago's museum dedicated to the history of bondage and fetishism is more textbook than titillation.

This massive World War II calculator hearkens back to the days when "computer" was a job title.

An easy-to-miss garden in Boston's North End honors the mother of JFK and others who lost children in WWII.

It's not a typo, now say it five times fast!

"Mock all and sundry things, but leave the saints alone."

"the sweltering inhabitants of Charleston and New Orleans, of Madras and Bombay and Calcutta, drink at my well . . . The pure Walden water is mingled with the sacred water of the Ganges."

Radical Bookstore and Community Space.

This small section of the Sleepy Hollow Cemetery is rotten with famous authors' graves.

Over fifty whirling pools left by the glacial age.

The walkable ruins of an 19th century hotel, destroyed in a horse cremation gone wrong.

The 340-year-old house that inspired the classic Nathaniel Hawthorne novel.

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!

The only structure left with direct ties to the Salem witchcraft trials of 1692.

Large Massachusetts museum dedicated to Armenian history and culture.