[dropcap size=small]R[/dropcap]ecreational divers generally do not go deeper than 40m into the sea. If you’re a professional deep-sea diver, you could descend to a maximum of about 60m. The Oyster Perpetual Rolex Deepsea, however, is waterproof to 3,900m, thanks to its patented three-part case structure. It is a prime example of overengineering in horology – and that’s exactly how we like it.

One of the world’s most extreme watches, the Deepsea was recently updated for 2018. The 44mm timepiece now houses Rolex’s latest energy-efficient Calibre 3235, and has slimmer lugs, as well as a wider bracelet. It might not garner as much press as the much more wearable – and, well, probably much more useful – 40mm, multi-time zone, Pepsi-bezel GMT-Master II, but the Deepsea demonstrates how far traditional watchmaking can be pushed, while remaining (relatively) wearable.

Considering that even certain “practical” complications in mechanical watches – such as the ever-popular chronograph – are seldom used, and are probably more relevant as examples of engineering ingenuity rather than functional necessity, extreme watches like this serve one important purpose – to help us dream just that much bigger.

(RELATED: The 60-second watch brand guide: Rolex)