The Grand National is widely regarded as the world's most famous horse race and the most difficult on the calendar.
Tony McCoy has never won it, but he believes nothing compares to the feeling of riding in the National.
So, what is it like to race over the giant fences of Aintree amid the hurly burly of a 40-runner field?
McCoy, the 12-time champion jockey, talks BBC Sport through the emotions, the highs and the lows of the National.
Sitting in the weighing room before the off, you get that butterfly feeling in your stomach.
Horses and jockeys line-up for the start of the Grand National
It's not a nervous feeling, more the adrenaline pumping and an excited buzz.
But the atmosphere is more relaxed and more enjoyable than other races because of the occasion.
On your way down to the parade ring you feel very lucky and privileged that you're able to take part in it.
It's quite crowded as there can be 40 horses there at once and it's more difficult to find your ride. Down at the start, we might have a bit of a chat with the jockeys around us, but when we're called forward it gets serious.
As a jockey, one thing you're well aware of is the huge number of people in the grandstands, and you can't help but notice the obscene amount of noise they are making.
It can be difficult for the horses and there are some that will always handle the occasion better than others, but you just try to get yourself well placed to get a good start.
As soon as that tape goes up, that's when it becomes a horse race rather than a spectacle.
There's nothing that compares to that feeling of when you're approaching the first fence.
If you get around the first circuit and your horse is still going well, then that's when you can start believing that you have a realistic chance of winning the Grand National
It's probably the first time in about an hour that you don't notice the crowd and you're fully focused on jumping that first fence - and not following those horses that you think won't jump well.
You generally know in your heart after you've cleared that first fence whether you're going to get around or not, but there's nothing worse than falling at the first in the Grand National.
I've done it before and you end up just lying there, knowing that it's all over.
Another good pointer of how you're going to do - whether you're going to get round or not - is how well you clear the first ditch, the third fence.
Then, as you approach Becher's Brook, you just try to hunt away and try to keep your horse out of trouble.
If you're heading to Becher's behind a horse that's done it before, like Hedgehunter, you know there is a fair chance he'll get over it, but you've got to get your own horse over as well.
The next focal point is the Canal Turn, and it is key to get a good position - most jockeys tend to try to keep out wide and try to hit the corner. What you want is to be on the turn where you lose least ground.
And then comes the Chair. From a jockey's point of view it really doesn't feel that much different.
There's always been plenty of fallers there in the past and it's in front of the stands, so that's why it's so famous.
It's pretty similar to Becher's so you already know what you're going to be facing - you just try to treat it as another fence.
If you get around the first circuit and your horse is still going well, then that's when you can start believing that you have a realistic chance of winning the Grand National.
Fatigue doesn't really play a part at all and the only time it hurts is when you hit the ground - that's the only time you'll feel tired.
If you're still on your feet for the second circuit, then the less horses still in contention the better from your point of view.
McCoy clears Bechers Brook with Blowing Wind in 2001
When you cross the Melling Road for the second time, with just two fences left to jump, that's when you really know whether you're in with a chance of winning.
Obviously, the excitement kicks in then if you're going well enough and you're still in contention.
You're hoping to have a clear run and that you're on the right horse.
If you get to the line and you haven't won, the overriding factor will always be disappointment.
However, it's nice knowing you've got around and you're not in the back of an ambulance.
But as with every horse race the main feeling is that you want to win, and when it's the most famous horse race in the world you want to win even more.
Back in the weighing room it's pretty quiet and there are obviously a lot of disappointed people, but there will always be one person who is happier than they have ever been in their life.
Whoever that lucky person is will get to enjoy it more than anyone else, and hopefully that will be me on Saturday!
Tony McCoy was talking to BBC Sport's Russell Barder
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