The climb of Alpe d'Huez has become one of the more noted mountain stages. During the 2004 Tour de France it was the scene of a 15.5 kilometres (9.6 mi) mountain time trial on the 16th stage. Riders complained of abusive spectators who threatened their progress up the climb.[118][119] On this stage it is not uncommon for a low end estimate of the spectators in attendance to number 300,000.