sentence: Many trains use Chicago as a place to change loads and to change directions.
sentences_before: O'Hare International Airport, one of the busiest airports in the world, is a major center for air travel. Chicago has another airport called Midway Airport.
sentences_after: There is also a canal between Lake Michigan and the Mississippi River called the Chicago River. The Chicago River is the only river to travel backwards.
concept_name: train
headings: Chicago Travel
categories: Cities with more than 500,000 inhabitants