The Nereus, an unmanned research sub operated by scientists from the Woods Hole Oceanographic Institute, imploded on Saturday. The sub was pushing the limits of its design, exploring an area of the Kermadec Trench off the coast of New Zealand, almost 30,000 feet below the surface. It is survived by all the scientists who operated it, a large body of research that could not have been collected any other way, and (hopefully) the funding to build a replacement.