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.

The odd depiction of the Virgin Mary and baby Jesus is rooted in the Catholic Church's eradication of Catharism.

The giant skeleton sculpture is surprisingly well-traveled.

A dark, dank room in subterranean Manhattan was the site of a ghastly murder.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

The saddest little diner in New York.

Try not to get slimed in Tribeca.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A very classy 1920s-era bar right in Grand Central Station.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The factory for the popular Dumbo location, the Greenpoint shop is a quiet gem.

The final resting place of the tragic king and queen of the Jazz Age is tucked away in a small Maryland graveyard.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

A super-sized promotional trick that is now a D.C. landmark.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

The United States Capitol's former columns still stand.

A haunting tribute to pioneering photographer Clover Adams.

Parking garage where Bob Woodward met Watergate source "Deep Throat."

Daily lunch spot for many of Washington, D.C.'s cab drivers.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

This grand gothic brewery has been pumping out suds for over a hundred years.