Hidden

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

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

World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

The cave where two British judges hid in exile after sentencing the king to death.

A water pumping station disguised as a residential home to assuage concerned neighbors now tricks most passersby.

A small window on Via Piella offers a lovely and rare peek at Bologna's lost canals.

A roadside spring pooling in an old bathtub where anyone can stop and sip.

This wondrous waterfall rushing down a green-covered mountain wasn't discovered until 2010.

Six beautiful wooden giants are hidden around Copenhagen.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

The abandoned mine where American troops discovered a treasure trove of art and artifacts hidden by the Nazis.

During the rainy season, this temple is almost entirely submerged, accessible only by boat.

A secret garden in a picturesque Edinburgh village has inspired artists for centuries.

A subterranean shelter remains intact under a busy Paris railway station.

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.