A Los Angeles man can recall almost everything he's ever done since the age of five.
TV producer Bob Petrella, 58, remembers up to half the days of his own life in shockingly vivid detail.
He was diagnosed with hyperthymestia, meaning overdeveloped memory, after putting himself forward for a study about memory at the University of California last year.
The rare condition, also known as Super Autobiographical Memory, has been discovered in just four people around the world.
Scientists are still baffled as to how and why it happens and no cases have yet been recorded in the UK.
Mr Petrella recalls the day and date he first met a good friend, and all the conversations he's had on most days throughout the last 53 years.
He first discovered his amazing talent at primary school, when he could pass every test easily without even revising.
Mr Petrella, said: "I always had this amazing memory but I never liked to advertise it or boast to strangers.
"I remember things best when they interest me, whether that's sporting events, or historical or political dates, or just good days I've had in the past."
He added: "I remember everyone's telephone number. I lost my cell phone on September 24, 2006. A lot of people would panic... But I didn't have any numbers in my cell phone because I have them stored in my head."