how did the location of chicago influence its development
Geography of Chicago One special feature of the Chicago area was the now-vanished Mud Lake in the Des Plaines River watershed. During heavy periods of rain or when the Des Plaines overflowed its banks due to downstream ice dams in the early spring, the river would flow through Mud Lake to the South Branch of the Chicago River, forming a favorite portage for early traders and creating the path of the future I&M and Chicago Sanitary and Ship Canals. When the city we know today was initially founded in the 1830s, the land was swampy and most of the early building began on low dunes around the Chicago River's mouth. Indeed, Chicago's low lying geography, which ultimately became crucial to its boom town development (as the site of the Chicago Portage and canal), could not initially attract substantial early settlement because the tall grass prairie around its lake and river systems was underlain by hard packed glacial clay, making much of the area forbidding wetlands.[2] Thus, the paradox of Chicago's development as a city in the 19th century became taking advantage of this geography, but also overcoming its limitations.
Chicago "L" Chicago's "L" provides 24-hour service on some portions of its network, being one of only five rapid transit systems in the United States to do so.[note 2] The oldest sections of the Chicago "L" started operations in 1892, making it the second-oldest rapid transit system in the Americas, after New York City's elevated lines.