September 7th 2019 marked the 20th anniversary of a unique and remarkable study into how our brains age. But it's a story which has roots back in 1921. Almost all the Scottish children born in that year were given a test in 1932, when they were 11, into their thinking abilities. It happened again in 1947 with a second group of 11-year-old Scottish children born in 1936. The results of those two sets of tests were tucked away until, in 1999, Professor Ian Deary and his colleagues from the University of Edinburgh unearthed the orginal data and had the idea of inviting many of those original participants back to be tested again in a unique study. Over 500 volunteers from those born in 1921 and over 1000 from those born in 1936 came forward and ever since their thinking skills have been closely studied and scrutinised, tested and their brains scanned to see whether they might reveal some of the secrets to ageing well. What impact does your thinking ability at the age of 11 have on your thinking ability as you reach old age? Are there particular activities, hobbies, careers or behaviours which contribute to healthy cognitive ageing? Why do people who drink more alcohol seem to perform better on cognitive thinking skills tasks? Before you raise a glass in delight, the answer is not as straightforward as you might think! The richness of the data collected by the Lothian Birth Cohort Studies over the past 20 years is unprecedented and has contributed to over 500 papers. The participants themselves have become global superstars in the fields of neuroscience and cognitive ageing. In this special Brainwaves, Pennie Latin joins the 20th anniversary celebrations in Edinburgh, hears from Professor Ian Deary and his team and meets some of the participants themselves, including 98-year-old Margaret MacKie who still does the Scotsman cryptic crossword everyday and says her ambition is to complete it six days in a row! It's a remarkable success story of a unique collaboration between a generation of Scots and a pioneering team of researchers that will leave a legacy we all might learn from.