The 'banging' sound that kept the hopes of families and rescuers alive in the search for the doomed Titan submersible has been revealed for the first time in chilling new audio. Played for the first time in a new ITN documentary, the hollow sound has a regular, steady beat which caught the attention of experts - and sparked hopes that the noise could be SOS signals being made by the five men on board. 🎥 Channel 5/ITN Productions #titan #titansub #titanic #submarine