Ride the subways of yesteryear.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

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

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

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

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

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

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

A crumbling hospital from the 1850s on Roosevelt Island.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Nose around a unique collection of more than 300 natural aromas used to craft perfume fragrances.

Travelers exchange letters with woodland creatures at this mini post office.

A storybook European village in Berkeley.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

A curious collection of locks and keys.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

The post-apocalyptic remnants of a bucolic town ruined by a plane crash.

Abandoned medieval hill town.

A cherry tree growing atop a mulberry tree.

A fake medieval village in the middle of Turin.

The Mighty Wurlitzer organ continues to belt out the tunes at downtown El Segundo's historic home for silent and classic movies.

Former 1954 Del Mar Train Station now serves signature cocktails and delightful culinary treats, and still operates as a Metro stop.

The abandoned train depot now doubles as a well-placed rest stop for those who take the road less traveled.