Answer:
St Lawrence Seaway
O' Hare Airport.
Step-by-step explanation:
The boom years happened during the 1940s and 60s because people were eager for starting a new life after the Great Depression and World War I and II. The Baby Boom period created demand like houses, daycare facilities, cars, and doctors. At the same time, infrastructure was making progress, which included St. Lawrence Seaway and O' hare Airport.
St. Lawrence Seaway is a canal built to connect all the Great Lakes in Canada. It joins the US and Canada through which ships travel from the Atlantic Ocean to Lake Superior by transporting goods and trade with others.
O' Hare Airport is an International Airport in Chicago opened in 1945, and it became one of the busiest airports in America.