The annual puzzle for punters returns, with so many horses to choose from in the Randox Grand National.
The 40-runner race has 30 fences for the horses to jump, over a marathon distance of four miles and two-and-a-half furlongs.
Red Rum and Tiger Roll are the only runners in the past 60 years to have won it more than once, which shows the challenge the race presents.
First prize is £375,000 and a place in Aintree history.
So what do you look for when trying to find the winner? Here’s Mirror Racing’s handy guide…
Form and rating
Punters can see a horse’s form next to their name on the racecard.
Number one and top weight Bristol De Mai has the highest rating, as he has won at the top Grade 1 level in the sport.
The National is a classy race these days and eight of the past ten winners were rated between 148 and 160.
In this afternoon’s field, that includes horses from number three Yala Enki down to number 30, Minellacelebration.
The Aintree feature is over a long trip – and some horses just won’t keep going strongly enough to stay the distance.
The last ten winners had all won over at least three miles.
Horses with plenty of stamina include Burrows Saint, as he took the 2019 Irish National and Takingrisks, who race to victory in the Scottish version two years ago.
Age and weight
The key ages for National horses is between eight and 11.
Seven runners fall outside of this range.
In the last decade, horses have carried weights from 11st 9lb and 10st 3lb to victory.
Six of the last ten winners of the Grand National carried 11st or less.
Given its unique test, it is surprising that seven of the last ten winners had not run over the National fences before.
So don’t let that put you off.
Vieux Lion Rouge holds the record for the most Grand National fences jumped, with an impressive 223 obstacles under his stride so far.
Favourite Cloth Cap is one of the Aintree newcomers.
Longshots have excelled in recent years.
In 2013, Auroras Encore stunned punters at odds of 66-1, while Neptune Collonges (33-1) prevailed in the closest finish to the race in 2012.
With so many runners, there is always the chance a horse may not get the clearest of runs or not take to the fences.
Seven of the last ten winners had a starting price of 14-1 or higher.