These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

Software company Epic Systems has created one of the strangest and largest workplaces of all time.

To find the "unicorns of the deep" you've got to go downstairs.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

Get past the gatekeeper's apartment and enter an elaborate hoax of a restaurant with a Masonic feel.

A science fiction-inspired apartment building designed by a famous Spanish architect.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The 43-mile route crosses through six islands with gorgeous views of the Seto Inland Sea.

Soak up some local history in this restored Edwardian era swimming pool.

A fashion designer's dazzling world of Japanese collectibles is hidden in a warehouse downtown.

One of Chicago's last seafood smokehouses perfects a dying breed of fishcraft.

What if all public housing projects had been designed by "the Pygmalion of modern architecture," not only their prototype?

Once one of the largest producers of pig iron in the world.

The skeletal frame of a decommissioned gas-pumping station offers breathtaking views of greater Berlin.

A luxurious 1880s hotel with its fair share of Tiffany stained glass, Edison electricity, and of course, ghosts.

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

During Prohibition, the U.S. Congress had an "official" bootlegger, with his own Capitol Hill office.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

Home to a vast and influential collection of Shakespeareana.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The "lovely red Vega" of the legendary record-settling pilot.