A giant 400-acre preserve in North Florida for displaced wolves.

Internationally recognized group that works to protect the wolf and educate the public about its plight.

A suburban street in Anchorage doubles as a runway, and each home has its own airplane hangar.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

Curtiss is a forgotten figure in the early history of flight.

The remains of a failed subway in upstate New York is now an underground graffiti bunker.

A layered tribute to the work of mosaicist Isaiah Zagar.

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

This forgotten building was one of the few Philadelphia-area breweries to survive Prohibition.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

The first American axe throwing club.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

This frozen tunnel in central Alaska is both an engineering feat and a valuable climate classroom.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

A century-old network of freight tunnels underneath the city's historic business district.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

The world's longest and deepest train tunnel.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

100 years later, they're still down there.

A painfully obvious spy house sits right across the street from the Russian Embassy.

These abandoned waterworks are crumbling into the Potomac River.

A former major munitions plant that has been converted into a sprawling art space.

This simple stone memorial remembers a secret, Geneva Convention-defying interrogation base from WWII.