Much of the housing stock was erected between 1905 and 1915. Most of the houses built before 1905 were wood-frame houses; that year, a zoning ordinance was passed, requiring new buildings to be made of masonry. The area was developed more quickly after the Queensboro Bridge opened in 1909, connecting Queens to Manhattan. According to a 1909 issue of the "Real Estate Record and Guide", development was concentrated in an 150-block area around East Williamsburg in Brooklyn, namely the present-day area of Ridgewood. More than five thousand buildings were built from the beginning of the 20th century to World War I's start in the mid-1910s. Residential construction predominated in the southern part of Ridgewood while industrial factories and mills were prevalent in the northern section, near Newtown Creek.