Paris-Brest-Paris is a long-distance cycling event that takes place in France, covering approximately 1,200 kilometers. It is held every four years and attracts cyclists from around the world. The route starts in Paris, travels to Brest on the northwest coast, and returns to Paris, challenging participants with varied terrain and weather conditions. The event was first organized in 1891 as a race and has since evolved into a randonneuring event, emphasizing endurance over speed. Cyclists must complete the course within a set time limit, typically 90 hours, while following specific rules and checkpoints along the way.