Developed after the completion of Prospect Park in the 1870s, Park Slope is primarily residential, with countless row houses and apartment buildings - the neighborhood is divided into three smaller communities - North Slope, Center Slope and South Slope. The population is typically young professionals attracted by the proximity to Manhattan and the low cost of housing. The commercial districts lie along 7th Avenue and on 5th Avenue, especially south of 9th Street. Experts agree that the defining moment here was 1995, when most of the wonderful Victorian and Romanesque Revival brownstones went over the million dollar mark - and what used to be considered a terrific area for middle-income families nowadays seems more fitting for Wall Street types. Seventh Avenue was once the outermost border of desirable Park Slope, but of late the boundary has reached Fifth.