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

Elevated freight railway turned wildly successful urban park.

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

The final resting place of a famous 19th-century murder victim whose identity is still a mystery.

The remains of a century-old mansion that met a fiery demise years after it was deserted.

A recently abandoned psych ward at the end of Sanatorium Road.

Once in a state of dilapidation, this candy-inspired fortress is now being revived.

The remains of a 19th century spring, and the site of an infamous unsolved murder.

Series of storm drains connected to a dark urban legend.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.