Patek Philippe Perpetual CalendarWhat youre looking at is arguably one of the most beautiful perpetual calendar watches ever made, full stop. And perhaps one of the most important, too. The reference 3940 was born in 1985, at a time when the watch world was in the midst of the Quartz Crisis and most brands were churning out inexpensive, battery powered watches and struggling to stay afloat. Alas, Patek Philippe was never one to follow the crowd, and released the ref. 3940 perpetual