Eidetic Memory

Eidetic comes from Greed word eidos which means "seen". Eidetic memory means the ability to recall any visual/audio events with perfect accuracy and details. People who claim to have this kind of memory possess the skills to exactly remember an event, for example the event in a ball room, where he/she can recall where the person was standing, the people around him/her, the shirt they were wearing, food they ate down to what kind of conversation that they were having.

There are several series depicting a genius with this kind of memory for example Dr Spencer Reid in Criminal Minds and Dr Sheldon Cooper in The Big Bang Theory. In real life however, the case of eidetic memory have yet to be understood fully but there are a few who claim to have this memory for example Stephen Wiltshire, a British architectural artist that can draw a landscape after seeing it once. Another person, Daniel Tammet, also a British citizen, who can recall the number pi up to 22 000 digits.

Dr Spencer Reid holds Ph.D in Math, Chemistry and Engineering
as well as B.A. in Philosophy.

Dr Sheldon Cooper portrayed by Jim Parsons in The Big
Bang Theory.

Psychologically, people who have eidetic memory sometimes suffer from a condition known as autism, a medical condition characterized by problems in social interaction and communication together with repetitive behavior. Generally, people who have eidetic memory suffer also with autism but people who suffer from autism may not have eidetic memory.

The video is a documentary about Daniel Tammet

There are several myths involving photographic memory especially as to whether normal people can acquire it or not. Most of the techniques that claim to help you acquire this memory are actually memory improvement technique, not the actual eidetic memory. Nevertheless, it is always good to improve your memory as it may helps you from time to time.

Source: here and if you like to read about some of the myths, you can go here.