The Underground tours!!! So cool and spooky. Not sure about this particular company, but in general totally worth doing. Underground opium dens, prostitution, speakeasies and shanghaiing (see : http://en.wikipedia.org/wiki/Shanghaiing).
The High Line. One of my favorite places in NYC. The High Line is a public park built on a historic freight rail line elevated above the streets on Manhattan’s West Side. It runs from Gansevoort Street in the Meatpacking District to West 34th Street, between 10th and 11th Avenues. To see some beautiful videos of NYC please visit http://www.dronezon.com/best-drone-videos/beautiful-drone-videos-of-new-york-city/