The Commissioners' Plan of 1811 called for twelve numbered avenues running north and south roughly parallel to the shore of the Hudson River, each wide, with First Avenue on the east side and Twelfth Avenue on the west side. There are several intermittent avenues east of First Avenue, including four additional lettered avenues running from Avenue A eastward to Avenue D in an area now known as Alphabet City in Manhattan's East Village. The numbered streets in Manhattan run east-west, and are generally wide, with about between each pair of streets. With each combined street and block adding up to about , there are almost exactly 20 blocks per mile. The typical block in Manhattan is .