If you want to learn a tree’s age, you can count their rings. When it comes to humans, scientists have yet to find any visible traits that mark our age with the same specificity. But in the past few decades, they’ve discovered small, invisible markers hidden within the body that do change over time. Juulia Jylhävä shares what these markers can tell us about our health, history, and future. Lesson by Juulia Jylhävä, directed by Flaka Kokolli, Diellza Franca, Flammorum Animation Studio.