The Patek Philippe Nautilus 3700/1A is the original “Jumbo” that started it all—a legendary reference introduced in 1976 and credited with defining the entire category of luxury stainless steel sports watches. Designed by Gérald Genta, its bold porthole-inspired case, slim profile, and integrated bracelet were revolutionary for the era and have since become one of the most iconic silhouettes in horology. Measuring 42mm across the widest point (including the “ears”), the 3700/1A earned the nickname “Jumbo” for its size at a time when large watches were far from the norm. The dial features a deep blue color with horizontal grooves, paired with simple white gold hour markers and hands, and a date window at 3 o’clock. It’s a minimalist execution, but its subtle gradient and elegant proportions give it unmistakable character. The monobloc case and ultra-thin self-winding movement (originally based on the JLC 920 ébauche) allowed the 3700 to maintain a thickness of just 7.6mm, contributing to its comfort and refined appearance. Despite being marketed as a sports watch, its design and finishing were pure haute horlogerie. Produced until the early 1990s, the 3700/1A is one of the most collectible steel Patek Philippe watches ever made. Early examples with the original “Type 1” bracelet and “Sigma” dials are especially sought after. As the founding member of the Nautilus lineage, this reference holds a level of historical significance that transcends trends—it’s not just the first Nautilus, it’s a cultural touchstone in the watch world. Whether admired for its design pedigree, mechanical innovation, or mythical status among collectors, the Nautilus 3700/1A remains one of the most important sports watches ever created. For those seeking the genesis of the steel luxury sports watch phenomenon, it simply doesn’t get more authentic than this.