sentences:  The southern end of the street was an integral part of the city as a main river crossing at various incarnations of the Rush Street Bridge across the main branch of the Chicago River from the mid-19th century until the 1920s.The Rush Street Bridges have a rich cultural history, which includes both a prominent role in facilitating vehicular land traffic and a prominent role as a commercial port location.However, commerce on the Chicago River has declined since the 1930s and the Michigan Avenue Bridge has taken over the role as the primary river crossing for this neighborhood.