The search for missing Malaysia Airlines jet MH370 has dropped out of the headlines recently, but the mission to find what remains of the doomed plane go on.
Now a team of drones has joined the search, travelling to depths that human explorers would find almost impossible to withstand, even inside the strongest submarines.
Search teams are using a Bluefin 21 sub - a robotic drone - to descend to the very floor of the Pacific Ocean. It has been sent to follow signs of four signals received on the surface shortly before the batteries on the plane's black box beacon died.
The US Navy sub has a maximum operating depth of 4,500 metres, but has already exceeded that during the search - forcing its controllers to cut one dive early.
It is now scouring the ocean floor with a sonar, to try and build a map of the debris field.
Meanwhile 14 planes and 11 ships are searching a 62,000-square-kilometre area of sea. No pieces of debris have been found so far, and there is as yet no indication of why the jet flew so far off course and what happened to make it crash.
However, that's not to say the drones haven't found anything - or that they're not proving useful. The video at the top of this post has details about what data they have brought back, and why it could prove more useful than anything else found so far.