SL3-046-199 Chicago, Illinois, U.S.A. Summer 1973 One of the great cities of North America--Chicago--seen in this north-northwest-looking, low-oblique photograph, is third in population behind New York and Los Angeles. Located on the northern Illinois plains on the southwestern shore of Lake Michigan, Chicago covers an area in excess of 225 square miles (583 square kilometers), extends more than 25 miles (40 kilometers) along the lakefront, and then sprawls inland nearly 30 miles (48 kilometers) west of the lake. The city is a major Great Lakes port that provides the Mississippi River-Illinois River system access to the Saint Lawrence Seaway. As the commercial, financial, industrial, and cultural center of the midwestern United States, Chicago attracts many large conventions that bring thousands of visitors to the city. In addition to being one of the busiest air centers in North America, Chicago is a major railroad and highway hub, also. Industries include large grain mills and elevators, iron and steel works, steel fabrication plants, stockyards, printing and publishing houses, electrical and agricultural machinery, musical instruments, communications equipment, electronic and computer equipment, furniture, chemicals, oil refineries, household appliances, foods and food processing, clothing, and tourism. Chicago is known for many historic events, but the Great Chicago Fire of 1871 might be one of the most well-known disasters in American history. Legend says that the fire started when Mrs. O'Leary's cow kicked over a lantern, and more than two-thirds of the city, built mostly of wood, was destroyed. Several hundred people were killed, and nearly 100 000 were rendered homeless. The city was rebuilt with stone and steel.