Memory man: Aurelien Hayman's hyperthymesia explained
The chances are you cannot remember exactly what you were doing on a given date years ago, unless it was your wedding or some other big event.
Aurelien Hayman is different because he can often he remember what he did, tell you what he was wearing, what he ate, what was in the news and even the weather.
The 20-year-old from Cardiff is one of only a handful of people in the world with hyperthymesia, or highly superior autobiographical memory.
Prof Guilianna Mazzoni, head of psychology at Hull University, has been putting him through a series of tests, and both appeared on BBC Breakfast.
The Boy Who Can't Forget: Channel 4, 21:00 BST, Tuesday, 25 September.