In the 1990s, hydrophones recorded a low, powerful pulse that traveled thousands of kilometers — and then vanished. This is one of the deepest ocean mysteries. ▶️ Watch the full documentary: Decoding the Enigma of Earth’s Deepest Oceans - [ • Decoding the Enigma of Earth’s Deepest Oce... ] 🔔 Subscribe to NEXION for more investigations. Vote in comments: Ice quake, geological event, or something stranger? 👇 #DeepSea #OceanMystery #NEXION #DeepSea #OceanMystery #NEXION