Defending champion Chris Froome looks set for a rocky ride with an army of hungry rivals trying to prevent the Briton becoming the first rider for more than 20 years to retain the Tour de France.
"This is the toughest challenge I've faced in my career, to target a third Tour de France," Froome, who prevailed on the French roads in 2013 and 2015, said.
The 31-year-old will hope that his performances are not scrutinised with the same negativity as last year when he faced a barrage of doping insinuations after smashing his rivals in the first mountain stage.
Team Sky's Froome, who won the Criterium du Dauphine warm-up race earlier this month, proved last year that he could be impervious to outside pressure, hanging on to his lead despite the media attacks and those coming from the crowd, which included having urine thrown at him during one stage.
A race that never ceases to throw up controversy will also be keen to stamp out rumours of illegal mechanical assistance.
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It is a threat so serious that organisers and the International Cycling Union (UCI) announced they would use thermal cameras to detect and deter hidden motors.
To help Froome succeed, Sky have assembled arguably the strongest squad around their leader, with Geraint Thomas, Mikel Landa, Sergio Henao and Wout Poels earmarked to protect him in the mountains.
"It's not just about beating Froome. It's about beating the whole Team Sky," Tinkoff's Alberto Contador told L'Equipe.
For the Spaniard, who won the Tour in 2007 and 2009, there will also be the small matter of beating Colombian Nairo Quintana, the best pure climber in the world.
"This will be the best version of Nairo," Movistar team manager Eusebio Unzue said.
"He's now more confident, more prepared, with a higher level of experience.
"Now he is ready to win the Tour (after finishing runner-up to Froome in 2013 and 2015).
Other contenders include 2014 champion Vincenzo Nibali and his Astana team mate and fellow Italian Fabio Aru as well as Quintana's team mate Alejandro Valverde and former Froome lieutenant Richie Porte of Australia (BMC).
