ALPE D'HUEZ, France >> One of cycling's big attractions is that fans don't have to pay to watch - and they can get as close as they want to the riders.The sport paid for that unlimited access Thursday when unruly spectators interrupted the most iconic climb of the Tour de France.With fans pressing too close to an elite group of riders at the conclusion of the 21 hairpin bends up to Alpe d'Huez, top contender Vincenzo Nibali crashed into a police motorbike and later withdrew from the race, four-time champion Chris Froome received some undesired contact on his back, and yellow jersey holder Geraint Thomas was booed on the podium.