This 19th century train workshop is a treasure trove of railroad history.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

Largest Roman Catholic church in North America.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

A super-sized promotional trick that is now a D.C. landmark.

Giftshop catering to cryptozoologists and anyone with a sense of humor.

At 207 feet, one of the world's longest continuous escalators.

The site of the climactic scene from the classic horror film is now a historic landmark.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

Home to items never before seen by the public.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This smaller cousin of the Forbidden City has gone from ancestral sacrifice to tourist's whispers.

Home to over 200,000 artifacts, this museum attempts to guide visitors through the ancient history of Beijing and Imperial China.

Ming Dynasty necropolis raided during the Cultural Revolution.

This probably wasn't what Mao had in mind.

The most famous location in China was home to whole dynasties worth of imperial rulers.

Beijing's expansive subterranean hiding spot now crumbles away as a tourist destination.