This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

A legendary speakeasy bookstore returns from the brink.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

The shelves in the back of this thrift store are devoted to saving, not selling, retro tech.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

Anatomical cabinet holds unexpected treasures.

Vast network of air raid tunnels beneath Lombardy's capital.

Long-abandoned art nouveau baths beneath Milan's Piazza Oberdan.

Before there were doorbells this bronze ear was installed for visitors to announce their arrival.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

The giant skeleton sculpture is surprisingly well-traveled.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Beautiful mosaics cover the first stations opened on New York City's newest subway line.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

The oldest living tree in Manhattan comes shrouded in sinister legend.

Discover the taste of mold.

The site of the deadly Triangle Shirtwaist Factory Fire.

A staggering collection of photographs depicting medical, social, and historical change.