Canal Turn: often scene of dramaPICTURE: John Grossick (racingpost.com/photos)
The Canal Turn
Jumped twice during the race, the Canal Turn is perhaps the most distinctive fence jumped because of the tight left-hand turn that immediately follows.
Although not particularly difficult to navigate, the fence is often the scene of drama. In 2001 a loose horse, Paddy's Return, ran along the near-side of the fence, bringing down or blocking nine rivals.
More regularly, the Canal Turn out-wits novice National jockeys who, failing to set themselves for the sharp turn that follows, slither ignominiously out of their saddles and out of the race.
Becher's Brook: most famous fencePICTURE: Getty Images
Probably the most famous fence in racing, Becher's Brook is named after Captain Martin Becher, a veteran of the Napoleonic Wars, who partnered The Duke to victory in 1836 - the first of three results not usually accepted as part of Grand National history.
However, he achieved immortal connection to the race by tumbling into the brook that stands on the other side of the fence named in his honour when his horse refused. Becher stayed submerged in the filthy ditch until the field had thundered past. In a move that embodied the spirit of the Grand National, he then remounted and gave chase, only to part company again at what is now known as Valentine's Brook.
Once a notoriously tricky fence with a considerable drop on the landing side, safety considerations have since seen it lose some of its uniqueness.
Foinavon: smallest fence in racePICTURE: Edward Whitaker (racingpost.com/photos)
Not the most ferocious fence at Aintree but one of the most infamous. At just 4ft 6in, the fence the field jumps seventh and 23rd is the smallest in the race, but it will forever be associated with one of the most memorable incidents in Grand National history.
In the 1967 running of the race, Foinavon was sent off the 100-1 outsider among the field of 44 but wrote his place in the record books when the beneficiary of a remarkable pile-up that resulted in him being the only horse left standing.
Approaching the fence for the second time, 28 of the runners remained in the race, but all bar Foinavon and John Buckingam came unstuck when a loose horse veered right.
Although 17 of them eventually managed to give chase, Foinavon was so far clear he could not be caught. The fence was officially named after the horse in 1984.
The Chair: a formidable fencePICTURE: Getty Images
One of just two fences to be jumped once, along with the water jump, The Chair is the biggest fence on the Grand National course.
With a 6ft ditch beforehand, standing 5ft 2in in height and 3ft deep it is a truly formidable obstacle.
The narrowest fence in the race bar the aforementioned water jump, the landing side of The Chair is actually raised 6 inches, the reverse of Becher’s Brook which means the ground effectively comes up to meet horse and rider quicker than anticipated.
The fence was named after a chair which was situated next to the fence, from which a judge used to see if any horses had been beaten by a distance.
Valentine's: can still prove trickyPICTURE: Edward Whitaker (racingpost.com/photos)
Standing at 5ft on the take-off side and six inches lower on the landing side, Valentine’s is jumped as fence nine and 25 and is regarded as the lesser of the two brook fences on the National course.
Although not as tricky as Becher’s, Valentine’s still requires a near-faultless jump, especially as it comes immediately after the Canal Turn.
It is named after Valentine, who attempted to pull himself up at the fence, eventually getting over it before going on to finish third.