There are five distinct groups of residence halls on the Cal Poly campus. The five North Mountain halls, constructed in the 1950s, are the oldest on campus still used for residential purposes.[65] The six "red-brick" halls were completed shortly afterward in 1959.[66] The Sierra Madre and Yosemite halls were finished by 1968, and the Cerro Vista Apartments were completed in 2003. The Poly Canyon Village housing complex, with a similar style as the Cerro Vista apartments, was completed in 2009 at a cost of $300 million, making it the California State University system's largest construction project to date.[67]