As it turns 40, nothing spotlights the distinctiveness of the ultra-thin self-winding caliber 240 movement as aptly as the skeletonized Calatrava that has been a part of Patek Philippe’s regular collection since 2008. As of 2017, the new Calatrava “Squelette” Ref. 5180/1R in 18K rose gold 5N showcases the extremely rare craft of skeletonization alongside magnificent engravings to imbue the elegant mechanism with enigmatic sensuousness.