Over the last 100 years, we’ve seen global life expectancy double. Could it happen again? Technology reporter and psychologist Aleks Krotoski explores the frontiers of the extreme longevity pioneers. They've made their money in Silicon Valley. And with their technology solutions - PayPal, Facebook, cryptocurrencies - they've ushered in the world that we live in today, with all its unintended consequences. Some of them now want to solve the "problem" of aging, or even death, and they are making bigger strides than we may think. Can they? Should they? Bryan Johnson is a technology success story. In 2013, he sold his company to PayPal for $400 million, and now spends his time - and $2m annually - on the search for eternal life. He believes he has found the secret - or, at least, can find it in the thousands of scientific articles he and his team sift through for their protocol of treatments. The most unusual of which is infusing Bryan’s veins with the plasma of young people. Has he discovered the fountain of youth? A Pillowfort production for BBC Radio 4 New episodes released Mondays. If you're in the UK, listen to the full series of Intrigue: The Immortals first on BBC Sounds: bbc.in/3WEQS5W