Chicago Transit Authority, also known as CTA, is the operator of mass transit within the City of Chicago, Illinois and some of the suburbs. It is the second largest transit system in the United States and fourth largest in North America. The Chicago Transit Authority offers bus and rapid transit routes throughout the city, as well as to some suburban destinations. The CTA is a municipal corporation that started operations on October 1, 1947 upon the purchase and combination of the transportation assets of the Chicago Rapid Transit Company and the Chicago Surface Lines streetcar system. In 1952, CTA purchased the assets of the Chicago Motor Coach Company, which was under the control of Yellow Cab founder John D. Hertz, resulting in a fully unified system. Today, the CTA is one of the three service boards financially supported by the Regional Transportation Authority.