 Cycling is very popular in France, evident from the fact that the race of Tour de France attracts more than 12 million people who travel to witness the race first hand.The Tour de France also attracts a television audience of 3.5 billion people worldwide.In addition, the north of France hosts the one-day race Paris–Roubaix, known as one of the cobbled classics famous for the use of cobblestones or setts as challenging terrain, and as one of the five "Monuments" which along with the road racing World Championship are the most important one-day classic cycle races.