The Great Lakes made Chicago

One of the major advantages Chicago has is the Great Lakes. The Great Lakes offered easy transportation of goods in and out of Chicago, turning the city into one of the largest today through transportation of goods from eastern U.S. to the west. Without the formation of the Great Lakes roughly 10,000 years ago, Chicago would not be the city it is today.

The lakes rest upon an area known as the Great Lakes Tectonic Zone and were formed by the extension of tectonic plates over 1 billion years ago, creating the Midcontinent Rift. Another part of the lakes geography is known as the St. Lawrence rift, an active seismic zone which created the area for the lower lakes 500 million years ago. While the zone is active, it is not known for very many earthquakes which could cripple a city like Chicago.

Having being formed during the last ice age, the lakes became filled with water as the Laurentide ice sheet melted. Basins that were created by the ice glaciers became filled with water and now known as the Great Lakes. While the formation of the lakes occurred over 10,000 years ago, they were vital to the creation and industrialization of Chicago to one of the largest cities in the world today.

Images from Bing
Sources: http://en.wikipedia.org/wiki/Great_Lakes