 However, commuter suburbs began to have significant retail districts by the 1920s.In the 1920s, the store created new suburban locations such as Marshall Field and Company Store to remain competitive.After 1950, with the booming post-World War II economic/social climate with increasing suburban residential and commercial development, saw the construction of first "strip" shopping centers, followed by regional enclosed shopping malls along major thoroughfares and interstate highways such as the "Magnificent Mile" reduced the role of the "Loop"'s daily significance to many Chicagoans as downtown retail sales slipped and gradually additional business moved outward following first the streetcar lines and then the automobile.