The Longchamp Racecourse (French: Hippodrome de Longchamp) is a 57 hectare horse-racing facility located on the Route des Tribunes in the Bois de Boulogne in Paris, France. Built on the banks of the Seine River, it is used for flat racing and is noted for its variety of interlaced tracks and a famous hill that provides a real challenge to competing thoroughbreds. It has several racetracks varying from 1,000 to 4,000 metres in length with 46 different starting posts. The course is home to more than half of the group one races held in France, and has a capacity of 50,000. The highlight of the calendar is the Prix de l'Arc de Triomphe.