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

Cryptic messages embedded in the New York City sidewalk.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Great place to have a drink and a bite to eat in an atmosphere laden with New York's Bohemian past.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

A dilapidated dock tells the story of Titanic's missed arrival.

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

Elevated freight railway turned wildly successful urban park.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Visible below the waves are memorials to the city's Gold Rush dead.

Beach instrument turned bed and breakfast.