Architecture of New York City spread outward from where it originally began at the southern-tip of Manhattan Island into surrounding areas. In order to house the burgeoning population, farm land and open space in Upper Manhattan, the Bronx, Queens, Brooklyn, and Staten Island were developed into neighborhoods of brownstones, apartment buildings, multi-family and single-family homes. The density of this new construction generally depended on the area's proximity and accessibility to Manhattan. The development of these areas was often spurred by the opening of bridges and the connection of boroughs via public transportation. For example, the Brooklyn Bridge was completed in 1883 and connects Brooklyn and
Boroughs of New York City form the new Nassau County. The borough of Staten Island, concurrent with Richmond County, was officially the borough of Richmond until the name was changed in 1975 to reflect its common appellation, while leaving the name of the county unchanged. There are throughout the five boroughs of New York City, many with a definable history and character to call their own. Since 1914, each of New York City's five boroughs has been coextensive with a county of New York State – unlike most U.S. cities, which lie within a single county or extend partially into another county, constitute a county