The Grand National is defined by its obstacles. No other race in the world asks horse and rider to tackle fences like these, and several of them are famous enough to need no introduction. Here is a tour of the ones that matter.
How many fences, and how the course works
The National is run over 30 fences across two circuits of Aintree's National Course. There are 16 individual fences; most are jumped twice, while a handful, including The Chair and the Water Jump, are jumped only on the first circuit. The fences themselves have, since 2013, been built around a more forgiving plastic core dressed with spruce, one of a series of changes made to improve safety.
Becher's Brook
The most famous fence in racing, Becher's Brook is jumped as the 6th and 22nd. Its defining feature is the drop on the landing side, which is lower than the take-off, catching out horses that jump too boldly. It takes its name from Captain Martin Becher, who fell there in the first official Grand National in 1839 and sheltered in the brook as the field thundered over.
The Chair
Jumped once, as the 15th, The Chair is the tallest and broadest fence on the course, around 5 feet 2 inches high and preceded by a wide ditch. It stands directly in front of the grandstands, making it the race's most imposing single obstacle.
The Canal Turn and Valentine's
The Canal Turn (8th and 24th) is unique for what comes after it: horses must turn almost 90 degrees to the left immediately on landing, so jockeys angle their mounts in the air to save ground. A little further on, Valentine's Brook (9th and 25th) is another brook fence steeped in National folklore.
The Foinavon fence
The small 7th and 23rd fence is named after Foinavon, the 100/1 outsider who won the 1967 race after avoiding a famous melee at this very obstacle, proof that at Aintree, the fences write the stories.
For everything on the next running, the runners, the betting and the build-up, see our Grand National hub and the tale of the race's greatest champion, Red Rum.