This little museum is built on a theater that was once a wildly elaborate speakeasy.

A semi-scholarly approach to sex.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

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.

Storyville was New Orleans' historic red light district and hotbed of jazz music, sometimes referred to simply as "The District."

This knobby, drooping New Orleans oak is a favorite place both for climbing and for meeting giraffes.

A collection of oddities including Dr. Kevorkian's suicide device, the Thanatron.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

This macabre painting of a Shakespearean scene looks like something out of a nightmare.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

Buried for centuries, this hidden cellar is all that remains of London's medieval Whitefriars Monastery.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

The sumptuous ceiling was one of the last things Charles I saw before his execution.

A Roman spa buried deep beneath the City of London.

This secluded walkway overlooks a magnificently wild London green space.

A little slice of Japan and its aesthetics in London's Holland Park.

The secret wartime bunker built on the platforms of an abandoned Tube station.

The lab where the scientist made his groundbreaking discoveries is preserved on the basement floor of the Faraday Museum.

Explore nearly 400 years of English middle-class home life.

The Columbia Road Flower Market is now open every Sunday, rain or shine.

Eclectic final resting place of the controversial explorer.

This hidden green space is the city's second largest conservatory.