The line in the pavement denotes the boundary between New York City (on the left) and Westchester County (on the right), which runs, as it happens, right through the middle of the red and white house in the background. The house is a duplex, and, according to its mailboxes, its two apartments are located in different cities! (One is 4047 Dyre Avenue in the Bronx; the other is 788 South 5th Avenue in Mount Vernon.)
UPDATE: The city line actually passes just to the north (right) of this house, meaning the entire structure is located in New York City. A tiny corner of the lot that the house sits on (Lot 2) is in Mount Vernon, however, which may explain the Mount Vernon address (788 South 5th Avenue) on one of the mailboxes. Or perhaps that address comes from the adjacent lot to the north (Lot 1), which also belongs to the owner of the house and serves as the house's driveway. That lot is split almost evenly between NYC and Mount Vernon.