The importance of Southampton to the cruise industry was indicated by P&O Cruises's 175th anniversary celebrations, which included all seven of the company's liners visiting Southampton in a single day. Adonia, Arcadia, Aurora, Azura, <answer>Oceana</answer>, Oriana and Ventura all left the city in a procession on 3 July 2012.
Along with the Oriana, what's the other P&O liner with a name that starts with the same letter?
Oceana