Ben Pridmore can memorise seven packs of cards
Some of the world's finest memories are testing their recall abilities at the UK Open Memory Championships in London.
Twenty-six contestants from 11 countries are taking part in a number of disciplines in the two-day event.
In one of them, competitors will be given 10 minutes to learn the sequence of hundreds of playing cards.
World champion Ben Pridmore, from Derby, holds the record in this event, having correctly memorised 364 cards.
He will be joined at the championships by the youngest competitor, 15-year-old Eva Ball from Coventry.
She won the UK's Schools Memory Championship last month, by recalling 94 numbers, 137 words, 12 events and dates, 102 binary numbers and nine shuffled playing cards in sequence.
Christopher Day, general secretary for the championships, said this kind of skill has a very practical use.
"There's not one thing that we do as individuals that doesn't rely on memory.
"Everything relies on memory and without it, we would have no language."
Whether learning subjects for the school curriculum or trying to scale the career ladder, the better your memory the better your performance, he said.
The third annual championships are sponsored by the online brain training website Cannyminds and hosted by the Strand Palace Hotel.
As well as card sequences, contestants will have to learn random words, binary numbers, names and faces and decimal numbers.
The competition is conducted in exam conditions, say organisers, with contestants simultaneously given papers depicting the sequences.
After a set time, the papers are taken away and the contestants are asked to recall the sequence in the correct order.
Memory champ v BBC journalist