The passenger cruise ships "Diamond Princess" and "Sapphire Princess" were completed and delivered to the owner, Princess Cruises, on 26 February and 27 May 2004, respectively, at the Nagasaki Shipyard and Machinery Works of Mitsubishi Heavy Industries, Ltd. (MHI). These ships are a new generation of large passenger ships that will sail as the Grand-series of advanced vessels by Princess Cruises, part of the Carnival Group. New concepts are incorporated in the designs of the ships in which environmentally friendly power generation, propulsion, and waste treatment systems using advanced technologies have been installed onboard. Both sister ships are now in service along the west coasts of the U.S. and Mexico.