First of all they need to have athleticism to jump the monster Aintree fences, which are among the most challenging the world.
They also need speed. It can be very tough for a horse to make up ground in a Grand National from the back of the field due to the number of runners, therefore being able to jump well but also quickly is a key trait to possess.
But perhaps most importantly, any horse that wins the National will have stamina and heart in abundance.
Four miles of relentless galloping has the ability to knock the stuffing out of a horse meaning only the strongest can continue the effort all the way to the line.
There are a number of horses that live long in the memory as legendary Grand National winners and we take a look at some of them here:
Red Rum – When you think of the Grand National, you think of the great Red Rum.
The late Donald McCain Snr guided this horse brilliantly to an unrivalled three Grand Nationals, firstly in 1973, then 1974 and then amazingly in 1977.
McCain brought Red Rum for 6,000 guineas at Doncaster Sales in August, 1972, but he hobbled out of his stable lame a day after arriving at Southport.
Things were to get much better though.
Once he got him onto a racecourse, Red Rum won his first five races and then landed one of the most famous Grand National’s in living memory.
Rather fittingly he denied an equally as remarkable horse in the form of Crisp, who nearly carried top-weight to victory in the race but was caught in the final strides by a gallant Red Rum.
He made up a 15 length deficit at the final flight to defeat brilliant Australian steeplechaser.
A year later McCain found more improvement in the horse to carry top-weight of 12st to win the race by seventh lengths.
Quite amazingly, he went off at a starting price of 11/1 – surely one of the biggest “why didn’t I back it” moments in sporting history. But it was his historic third Grand National, won at the age of 12 that turned him as a sporting hero.
After a season of disappointment Red Rum found his best form at Aintree and after a last fence mistake by his main rival Churchtown Boy, he roared clear to the delight of the paying public.
Legendary commentator Sir Peter O’Sullivan famous words still lie in the memories of anyone who was involved with the race: “It’s hats off and a tremendous reception – you’ve never heard one like it at Liverpool. Red Rum wins the National.”
Don’t Push It – This was a huge win for horse racing as a sport as it propelled its greatest ever name into the spotlight.
Jockey AP McCoy’s win aboard the JP McManus owned Don’t Push It was the jump jockey’s first National win at his fifteenth attempt and subsequently played a huge part in him winning the BBC Sports Personality of the Year award.
The horse was as brave as they come too.
It’s not often you see a horse carry a big weight around Aintree to win the National but Don’t Push It managed it with 11st5lbs on his back.
Neptune Collonges – Last year’s race was perhaps the most exciting finish in Grand National history.
Not only was it champion trainer’s Paul Nicholls’ first ever winner in the race, the horse probably came the first horse to win a National having not been in front anywhere until the line.