An old timer when it comes to cruising, P&O Cruises dates back to 1837. The ships didn't boast spas and celebrity chefs back then — in fact, they were mail vessels that carried passengers on the side — but they've had plenty of time to perfect the cruising experience. Despite Black Tie Nights, this is a casual cruise line, well suited to the attitude of the Caribbean islands. Shore excursions are designed to showcase the British, French, Dutch and Spanish cultural influences of the region; they feature the history, architecture, markets and the natural wonders of such popular destinations as Antigua, St. Lucia and St. Kitts. Since cruises depart out of the UK, guests also enjoy stopovers in the Azores and the pleasure of a leisurely Atlantic crossing.