The "Seinfeld" diner.

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

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

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

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

New York City's smallest piece of private property.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A crumbling hospital from the 1850s on Roosevelt Island.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

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

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

Rusty pieces of metal jutting out of a breakwater are all that's visible of the 12,500-ton ocean liner that capsized just off the beach.

Once the site of speeding horses, now home to picnickers and public concerts.

A playing field for a popular French past time can be found tucked away in a quiet corner of Golden Gate Park.

Approximately 250,000 people left homeless by the great earthquake and fires found shelter in Golden Gate Park.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

Created in 1972, the famous sculptor's intricately detailed monument to San Francisco is overflowing with city landmarks.

Gold Rush ship-turned-hotel buried underneath San Francisco's financial district.

The remains of a 12th-century chapter house in Golden Gate Park.