The Grand National: Everything you need to know (almost)
The Grand National is one of the most famous and toughest horse races in the world - and it takes place this Saturday.
It's a very popular event and 600 million people watch it on TV all over the globe.
The race is part of a three-day race meeting held in Liverpool with over 150,000 people attending.
It's a huge event but it's not just about the horse racing - so we've put together a guide to the festival.
When did it all begin?
The first Grand National event at Aintree is believed to have been held in 1839, although some historians believe the first Grand National took place three years before, in 1836 - but on a different course.
The race was moved to Gatwick Racecourse between 1916-1918 during the First World War and was called off between 1941-1945 because of the Second World War.
The Grand National is held at Aintree Racecourse in Liverpool and during the three day event over 20 different races will take place.
In the biggest race, the Grand National, horses have to complete two laps of the course, covering four-and-a-half miles and jumping 30 fences.
There are 16 different jumps, known as fences, on the National Course. All 16 are jumped during the first lap but on the second lap of the circuit the horses only jump 14 of them.
Some of the fences have different names.
One of the most popular fences is called The Chair - it's the tallest on the course and the ground on the landing side is higher than the side the horses take off from. There's also a ditch horses have to jump over before the fence.
Campaigners and animal rights charities have often complained that the Grand National isn't safe for the horses involved and that the race is too dangerous.
In both 2011 and 2012 two horses died racing in the Grand National and charities like the RSPCA say that needs to change.
In 2011, 2012 and 2013 the organisers of the race made some changes to the course like making the fences and drops shorter to reduce the danger of the race.
But campaigners say more needs to be done.
A horse called Red Rum won the Grand National three times in 1973, 1974 and 1977 and also came second in 1975 and 1976.
Red Rum died in 1995 at the age of 30 and was buried near the winning post at Aintree.
In 1993, no-one won because there was a false start - some riders didn't realise and carried on so the race had to be cancelled.
Amazing Grand National facts
The oldest horse to win the race was Peter Simple, he was 15 years old and won in 1853.
Five horses have won the race aged only five years old.
The oldest winning jockey was Dick Saunders in 1982 aged 48.
Bruce Hobbs was only 17 when he won in 1938.
In 1929 an incredible 66 horses started the race but only two finished in 1928.
All this horse chat in the Newsround office has led to us telling each other some of our favourite horse-related jokes so we thought we'd share some of the better ones with you.
Q: When do vampires like horse racing?
A: When it's neck and neck
Q: What do horses fear most?
A: Hay Fever!
Q: Why can't horses dance?
A: Because they have 2 left feet
Q: What do you call pony with a sore throat?
A: A little hoarse
Q: What's a horse's favorite sport?
A: Stable Tennis