Over the last 100 years, we’ve seen global life expectancy double. Could it happen again? In The Immortals, 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 they've ushered in the world that we live in today. Some of them now want to solve the problem of aging - or even death itself - and they are making bigger strides than we may think. Can they? Should they?

A Pillowfort production for BBC Radio 4