A hidden "place of interment for gentlemen."

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Sniff the Titan Arum's rotting flesh.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

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

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

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

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Read a book next to a Midtown waterfall.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

The "Seinfeld" diner.

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

A dilapidated dock tells the story of Titanic's missed arrival.

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

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Elevated freight railway turned wildly successful urban park.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

This hilltop park offers magnificent views and a Frank Lloyd Wright masterpiece.

Most famous work of one of Frank Lloyd Wright's sons.

This once-booming gold mining hub was basically abandoned overnight.

Where the writer penned his famous story about a jumping frog.