Petty Officer 3rd Class Jonathan Gonzales, a boatswain's mate aboard the USCGC Sequoia (WLB-215), homeported in Apra Harbor, Guam, prepares to throw a grappling hook to retrieve a National Oceanic and Atmospheric Administration hydrophone from Challenger Deep near the Federated States of Micronesia, Nov. 3, 2015. The crew of the Sequoia and NOAA scientists deployed the hydrophone in an attempt to listen to ambient sound in the deepest part of the Challenger Deep. (U.S. Coast Guard photo by Petty Officer 3rd Class Dylan Hall/Released)