Patek Philippe Aquanaut

The Aquanaut is the Nautilus's younger, more laid-back sibling, launched in 1997 to bring Patek's sports-watch idea to a new generation. It shares the integrated-bracelet DNA but loosens the collar: a rounded octagonal case, an embossed checkerboard dial, and a composite "tropical" strap that was genuinely radical for a house like Patek when it arrived. Steel is the heart of the line, though it also comes in rose gold, along with chronograph and travel-time versions for more reach. It wears sportier and more casual than almost anything else Patek makes. Think of it as the door into Patek's sports-watch world, assuming you can get one, which is its own challenge.