In some respects, advanced submarines are a kind final boss of sorts in the world of naval warfare. Stealthy and well armed, for many nations these resource intensive platforms have underpinned naval strategy and nuclear deterrence for years. Investments in submarines and their associated industrial bases have been on the rise in countries like the USA and PRC for years, and we've seen new powers either obtain or seek to obtain nuclear submarine capability. But much of the value of the submarine comes from the assumption that submerging brings stealth. And with new or predicted technological developments, some are predicting that in coming years or decades, that assumption may no longer hold true. So today, we look at submarines, some of the technologies that might threaten them, and ask what the future might bring for these underwater hunters.