On March 1, 1999, NOAA hydrophones picked up a strange, long, mournful sound in the Southern Pacific, quickly nicknamed “Julia.” The noise lasted for nearly 15 minutes and was so loud it was detected over 5,000 km of ocean. While NOAA attributed it to a massive iceberg grounding on the Antarctic seafloor, cryptid enthusiasts dubbed it the “Julia Monster,” speculating that something vast and unknown was moving beneath the ice. The recording has since been tied to theories of hidden leviathans in Earth’s most remote waters.