Global permission to mine the ocean floor — the International Seabed Authority will soon meet and decide whether or not to allow seabed exploitation, and in what circumstances. We'll hear the arguments both for and against and get some background on this little known, but hugely consequential, international regulatory body. Also, will advanced technology one day make the oceans transparent? And if so, what will that mean for the future of submarines – a technology that relies on stealth and secrecy? And why studying ancient tsunamis could help protect us from future disasters.