The 2016 Tour de France will be decided in the final week of racing, according to two-time champion Alberto Contador.
Four stages in the Alps near the Swiss border provide a tough end to the 103rd edition of the race and the general classification is expected to be up for grabs ahead of the procession to Paris on July 24.
Chris Froome is favourite to retain the title at the end of the three-week Grand Tour, but Contador believes the winner of the yellow jersey will still be contested until the very end.
"It will be a unique Tour," he said. "It'll be very tough from the start, but for me the last week will be the most important of the race.
"The race will be open until the end, because the Queen stage is on the last day in the mountains."
This year's Tour was expected to be Contador's final appearance ahead of his retirement, but the 33-year-old has shelved those plans and suggested he could ride on for another two years.
He added: "Things [his future] are still open, things are going well, but nothing is closed at the moment.
"I'm really calm about it all. I'll probably be here for two more years, but now the most important thing is to concentrate on the Tour.
"I've worked hard to win it. Tinkoff is now my tam and has been since 2012. The team has always supported me. This is the last year and so the best thing I can do is to win the Tour and pay Tinkov back for everything."
The Spaniard will be assisted by Peter Sagan - who has won the last four points classification jerseys - and the Contador spoke highly of the Slovakian world champion ahead of stage one.
"I feel fortunate that I can share the team with Peter," he said. "I think he's one of the classiest riders I've seen during my career.
"He can do everything and he can make the difference in a tactical situation and so it's not a problem to be in the same team as Peter, it's a privilege."