Extract the answer to the question from the following context. Question: The streets grew why? Context: In the 19th century, the city was transformed by development relating to its status as a trading center, as well as by European immigration. The city adopted the Commissioners' Plan of 1811, which expanded the city street grid to encompass all of Manhattan. The 1825 completion of the Erie Canal through central New York connected the Atlantic port to the agricultural markets and commodities of the North American interior via the Hudson River and the Great Lakes. Local politics became dominated by Tammany Hall, a political machine supported by Irish and German immigrants.
Answer:
the Commissioners' Plan of 1811