The world today is getting older, and one of the legacies of the 20th century is longevity. After the Second World War there was a rapid reduction in mortality around the world, including in middle- and low-income countries. In 2015 there were already 810 million people aged 60. The estimate is that every two seconds a person turns 60. These extra years are an unprecedented privilege. We are in fact living through a longevity revolution.