This humble historic facade hides a history of boozing and the gentlemanly sport of rat-fighting.

A hidden "place of interment for gentlemen."

A trove of century-old litho stones from the Puck Building's printing days were discovered behind a cellar wall, and are now hanging in the store.

Plot your trip through the city on the sidewalk.

The former sign of this immortal music venue is just that--undying.

New York's unstoppable progress turned this cemetery into the smallest burial ground in the city.

Stunningly detailed mosaics in a New York subway station bring life to the Weimaraners of artist William Wegman's work—and to thousands of commutes.

This historic building housed the surviving crew members of the Titanic, who were left destitute after the wreck.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

Possible relics of the ancient Roman city are hidden in this restaurant's façade.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

A hidden medieval crypt where a famous legend says the devil used to teach black magic.

An architecturally unique lighthouse that had to be lifted up and moved to avoid falling in the sea.

The lighthouse central to the 1980s horror classic "The Fog" is, in fact, located in one of the foggiest areas of the Pacific Coast.

Concrete strongholds stand guard over the Golden Gate.

A hidden subterranean installation offers a view of the sky.

Art in the form of a winding, man made crack in stone.

San Francisco's first World's Fair, dedicated to the wonders of California.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

A New England-style lighthouse along California's beautiful Highway 1 gets a re-do.

A psychedelic tribute to one of Georgia's most unique artistic visionaries, out of place and time in the heart of Atlanta.

This small memorial is almost as well concealed as Smalls himself was on the night he sailed to freedom.