‘In this world nothing can be said to be certain, except death and taxes.’ While Benjamin Franklin’s quote remains true for most, the same might not be said for some of the world’s billionaires. And their efforts to extend life are under way too. Most recently, a Silicon Valley startup called Altos Labs signed up a dream team of scientists, including numerous Nobel laureates, with an aim to rejuvenate human cells. In this episode from February 2022, Ian Sample speaks to Prof Janet Lord about the science of ageing, extending our health as well as our lifespans, and how old we could actually go. Help support our independent journalism at theguardian.com/sciencepod