This week marks the 500th anniversary of the Kiplingcotes Derby - England's oldest horse race.
It's also one of the quirkiest - a chase across the flatlands of the Yorkshire Wolds that can be contested by almost any horse or rider, no matter their age or ability.
Gallery: The Kiplingcotes Derby through the ages
2018 brought controversy to the event - which was first run in 1519 - after damage to the course by off-roaders meant that the race could not be run.
Fortunately it's been declared safe this year and will go ahead as normal.
The third Thursday in March every year at 11am.
What is the course?
It's four miles across tracks and fields, beginning from the former Kiplingcotes Station site in Etton, near Market Weighton. It finishes at Londesborough Wold Farm. A clerk is paid 25p annually for maintaining the route.
Who can ride?
The delightfully eccentric competition has few rules. Horses of any age can be ridden and the oldest jockey was 74. Former racehorses are often entered under fake names - a practice that's accepted as a quirk of the Derby. Any type of mount can take part, from ponies to shire horses. Many of the jockeys are recreational riders from the local area who simply fancy their chances, and outsiders have been known to win. The names of the riders are not declared until the day of the race - there are no advance entries, you just muster at the starting post on the day.
Can you place bets?
Yes - but there's only one bookie. Because Chris Johnson doesn't know anything about the horses until race day, he has to estimate their condition and pedigree before calculating his odds.
What's the prize?
The winner receives the Kiplingcotes Derby and £50. But come second and you could be quids in - traditionally the runner-up receives the remainder of the entry fees, which sometimes exceed the prize fund.
What happens if it's cancelled?
The race has only ever been called off three times in its history - and all have been in the past 100 years. In 1947, during one of the harshest winters in British history, it was cancelled due to huge snow drifts. In 2001 the foot and mouth outbreak made the gathering unfeasible. And in 2018 damage by off-road vehicles meant the course was too waterlogged to be safely run.
Traditionally, if the race is cancelled then it must be 'walked' by a steward on horseback to ensure it can be contested the following year, according to the ancient rules. Stephen Crawford performed this role in 2001 and 2018, while current trustee Guy Stephenson's uncle Fred had the honour in 1947.
Some other facts
- Horses have been known to die during the tough race. In 1997, the winning mare, Sunny, collapsed and died immediately after finishing. The runner-up, Burt, also died moments after the finish in 2002.
- It's been called 'the Brigadoon of racing' because the course will not be used again until the following year. Brigadoon is a mythical Scottish village that only appears for one day every 100 years.