Chris Froome has been the toast of the Tour de France for three of the past four years. Winner in 2013, 2015 and 2016, the Briton starts this year's Tour as the overwhelming favorite, despite yet being at his imperious best this season.
Froome runs to get another bike after falling during the 178 kilometer 12th stage of the 103rd edition of the Tour de France cycling race on July 14, 2016 between Montpellier and Chalet-Reynard.
The main threat to Froome's hopes of wearing the yellow jersey again is arguably Australian Richie Porte. At 32, he is a seasoned competitor and already boasts six wins this season. Porte was Froome's domestique -- a rider who works for the benefit of his team and leader -- at Team Sky and played a major role in Froome winning his second Tour de France crown in 2015. Now the lead rider at BMC, Porte will be looking to prove his Tour credentials.
Nairo Quintana knows what it feels like to be on the Tour de France podium -- but he's yet to stand on its summit. Twice second behind Froome in 2013 and 2015 and with a third place finish in 2016, the Colombian's strength lies in the mountains. Victorious in the two other Grand Tours -- the 2014 Giro d'Italia and the 2016 Vuelta a España -- Quintana could become just the seventh man in history to win all three.
Alberto Contador is one of those six riders to have won all Grand Tours, claiming victory in all three at least twice. The veteran 34-year-old may not have the legs he used to, but well over a decade of experience at the highest level means he will undoubtedly still be in contention.
Mark Cavendish, though not in contention for the yellow jersey, will be looking to write some history of his own. The British sprint specialist needs just five more Tour de France stage wins to become the most successful stage-winner of all time. Currently on 30 stage wins -- trailing Eddy Merckx's record of 34 -- Cavendish faces an uphill battle, as he only returned to training six weeks ago after contracting the Epstein-Barr virus.
Le Tour takes in some of the most breathtaking scenery in Europe. In 2016, Froome unexpectedly won the stage to Bagnères-de-Luchon by attacking on the descent. The Team Sky rider will need to produce similar stage performances this year, as the tour features the lowest number of time trial kilometers in history -- a discipline Froome excels in.
The five main mountain ranges of France -- the Vosges, the Jura, the Pyrenees, the Massif Central and the Alps — are all on this year's route. The Col d'Izoard -- the finish of stage 18 -- is pictured. A mountain pass in the Alps that is usually closed from October to early June, the last 10km before the summit of the Izoard are at an average gradient of 9%.
It is estimated that 12 million people will line the roadside for the Tour de France over the next three weeks.
Fancy dress for fans is optional ... Here Didi Senft known as El Diablo cheers on the riders during the 207 km fourth stage of the 93rd Tour de France cycling race from Huy (Belgium) to Saint-Quentin (France), 05 July 2006.
However, France remains in a state of emergency and on high alert to a possible terror attack. A French gendarme is pictured standing guard at the departure line prior to the start of the 209km sixteenth stage of the 103rd edition of the Tour de France cycling race on July 18, 2016 between Moirans-en-Montagne and Berne.