When Louis Cartier designed a square watch on a leather strap for his friend Alberto Santos-Dumont in 1904, he wasn't updating a convention, he was inventing one. The wristwatch existed before then, but it was jewelry, worn by women. The Santos was the first purpose-built wristwatch for a man, made because a pilot couldn't check a pocket watch while flying. The design language that followed from that moment, legibility, security on the wrist, a case architecture that's unambiguously a wristwatch and not a pocket watch dressed up, is still visible in every Santos Cartier makes today. A purpose built tool yet an elegant icon to this day, there are few watches that match the Santos in story and class.