The California Science Center is located at the heart of the 160-acre Exposition Park at the edge of Downtown Los Angeles. ZGF completed the park master plan, followed by design of the phased replacement of museum facilities, as well as other park improvements. The master plan recommended that the museum, which was previously housed in eight separate structures, consolidate its facilities under one roof on a site where one of the original buildings then stood. The 245,000 SF Phase I, incorporating a portion of the original building in its north fa├žade, includes a 483-seat IMAX theater, a semi-enclosed rotunda, and the main exhibition block of the museum. The Phase II expansion, named Ecosystems, was designed by the joint venture of ZGF and EHDD. This 140,000 SF addition complements the existing Phase I exhibits, adding new interactive and live exhibits that teach the principles of ecology using various global habitats, along with two floors of administrative office space, and new back-of-house facilities for the museum. The Phase 3, 200,000 SF Samuel Oschin Air and Space Center will house the Space Shuttle Endeavour, along with other air and space related exhibits and artifacts.