Hear the mysterious knocking sounds coming from the Titan submersible CNN 0 128 02.29 10:09 https://www.youtube.com/watch?v=CCXg1W-iJ6U + 11 https://www.youtube.com/feeds/videos.xml?channel_id=UCupvZG-5ko_eiXAup… + 11 Hear the mysterious knocking sounds coming from the Titan submersible