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Now to a report about an annual tournament that tests your memory. This year, London is hosting the British Open World Memory Championships. 22 competitors from 15 countries are taking part.
The winner of the World Memory Championships is called a "top memory master."
To get there, competitors have to overcome a series of memory-straining exercises.
The British Open tournament has ten challenges, including memorizing 4,500 random numbers within an hour and memorizing over 100 fictitious days and events within five minutes.
Ben Pridmore is a financial analyst. He has won the championships three time and this year is hoping for a fourth. He says consistent training is the key to success.
Ben Pridmore, "Top Memory Master" from Britain, said, "The most important thing is training, learning systems, developing new techniques. Natural ability is a very very small part of it."
11-year-old Konstantin Skudler from Germany is the youngest competitor at this year's championship. He won the under-12 group and has been competing here for five years.
Konstantin Skudler, 11-year-old competitor from Germany, said, "Because I can see how I get better. And I like it."
The World Memory Championships started back in 1991.
This year's international championship will be held in Guangzhou in December.
The World Memory Sports Council says it will be the largest championships in history with more than 100 sharp-minded competitors taking part.