A 1,215-foot tunnel transports pedestrians beneath the River Thames.

The curios of pharmacist and collector Henry Wellcome.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A kaleidoscopic warehouse-maze of handmade neon signs.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Love, knishes, and best wishes from this legendary Lower East Side bakery.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A very classy 1920s-era bar right in Grand Central Station.

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

The "Seinfeld" diner.

One of only two commuter aerial tramways in the United States.

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

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

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

Elevated freight railway turned wildly successful urban park.

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

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

This distinctive Crescent City tradition dates back to the days of horse-drawn carriages.

The beautiful, fruit-covered facade hints at this building's former life.

The world-record holder for the longest bridge stretching continuously over water.