Today we visit the Flatiron District in downtown Manhattan to tour 240 Park Avenue South, a jaw-dropping duplex penthouse on the market for $30 million dollars. 14 foot ceilings and full-height windows bathe the space in light while offering 360° views of the city and nearby Gramercy Park. Rising from the first floor all the way up to the rooftop pool is a stunning 24 foot green marble wall, uniting the space in dramatic fashion.