The Calatrava is Patek Philippe's signature model, created in 1932 and still much admired by the world of watchmaking for its pared-back aesthetics - a combination of sleek lines and refined elegance. The new Patek Philippe Calatrava Ref 5227 launched this year, and it embodies everything that has made the Calatrava such a legendary design. A traditional dress watch with no obvious superfluous design flourishes, it does, however, come with a significant innovation: an officer-style caseback, which opens to reveal the automatic caliber 324 SC movement. Hinged from the inside, it's almost invisible when closed. Crafted from white gold and finished with a shiny black alligator strap, the Calatrava Ref 5227 is another Patek Philippe classic.