'Final' Thai cave rescue underway, Elon Musk visits with 'kid' submarine

Rescuers have begun the third and most challenging phase of their mission yet - rescuing the four remaining boys and their soccer coach from deep inside northern Thailand's Tham Luang cave complex where they've been trapped for the past 18 days. Over the last fortnight, divers, engineers, medics and others have flown in from around the world to assist in the success. Among them -- American technology billionaire Elon Musk who went into the cave on Monday and left the rescue team with a "kid-sized" submarine his company SpaceX had built.