New Haven was one of the first planned cities in America. A year after its founding by English Puritans in 1638, eight streets were laid out in a four-by-four grid, creating what is commonly known as the "Nine Square Plan". The central common block is the New Haven Green, a square at the center of Downtown New Haven. The Green is now a National Historic Landmark, and the "Nine Square Plan" is recognized by the American Planning Association as a National Planning Landmark.