Your weekly bonus episode of The Global Story.

When OceanGate's Titan submersible went missing last June, it sparked a monumental rescue mission which captured the attention of the world. After days of searching, authorities concluded that the vessel had suffered a catastrophic implosion, and that all five passengers died almost instantly. For the past two weeks, the US Coast Guard has been hearing testimonies from former employees and industry experts, to try to identify what went wrong.

On this episode, Azadeh Moshiri is joined by the BBC's science editor, Rebecca Morelle, to discuss the most revealing evidence, and consider whether the tragic event could have been avoided.

The Global Story brings you trusted insights from BBC journalists worldwide, one big story every weekday, making sense of the news with our experts around the world.

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Producers: Laurie Kalus and Eleanor Sly
Sound engineers: Phil Bull and Mike Regaard
Assistant editor: Sergi Forcada Freixas
Senior news editor: Richard Fenton-Smith