The next chapter in the rivalry between seven-time Tour de France winner Lance Armstrong and defending champion Alberto Contador will take place in a majestic landscape next July - the Pyrenees.

Riders of the most prestigious three-week cycling race will celebrate the first crossing of the Pyrenees 100 years ago with as many as four stages in the daunting mountains that form the border between France and Spain.

Tour organizers unveiled the 2010 course on Wednesday, with Armstrong and Contador attending the ceremony in Paris. The pair worked together as Astana teammates during this year's race, and the Spaniard won the Tour for a second time while Armstrong finished third.

The 38-year-old Armstrong has since left the Kazakh-funded team to launch his own outfit, RadioShack, which has yet to be granted a ProTour license.

In 1910, Tour riders climbed the four legendary Pyrenean passes - Peyresourde, Aspin, Tourmalet and Aubisque - a feat their modern heirs will repeat next July. The Tourmalet, one of the toughest climbs in cycling, will be scaled twice.

Tourmalet is a nearly 2,150-meter (7,000-foot) peak that has been climbed more times (73) than any other in Tour history. But only once has it hosted a stage finish - in 1974, when French rider Jean-Pierre Danguillaume beat a field that included Eddy Merckx to the top. That year was also the last time Tourmalet was climbed twice in one Tour.

It has been nearly 41 years since the Tour sent the riders over all four of the Pyrenees' most punishing ascents in one day, in the 1969 Tour's 17th stage.

That epic race saw Merckx take off on an 140-kilometer (87-mile) solo breakaway, finishing first at Mourenx after crossing the peaks of Peyresourde, Aspin, Tourmalet and Aubisque on his way to the first of his five yellow jerseys.

The year that race first ventured into the Pyrenees, the 10th stage was a 326.7-kilometer (203-mile) epic journey over the same four peaks that riders will climb this year. Like Merckx in 1974, the winner of this stage, French rider Octave Lapize, went on to win the coveted yellow jersey. Lapize's judgment of the course's designers has become part of Tour legend: "You are assassins, yes, assassins."

Nicknamed "The Circle of Death," the combination of the four big mountain passes was also crossed in the 1926 Tour. Like in 1910 and 1969, the winner of that stage, Lucien Buysse, went on to win the Tour.

"We will follow in the wake of Eddy Merckx on this arduous succession of mountain climbs," race director Christian Prudhomme said. "With the celebration of the first crossing of the Pyrenees, it's logical that the Pyrenees will be harder than the Alps on this Tour."

The new course will include a total of 23 mountain passes in the Alps, Pyrenees, Jura and Massif Central, three more than this year.

The 2010 Tour will start with an 8-kilometer (5-mile) prologue in Rotterdam, Netherlands, on July 3 with a final stage on the Champs-Elysees after a 3,596-kilometer (2,234.5-mile) clockwise ride. In between, riders will go through Belgium and tackle six mountain stages including three hilltop finishes, four medium mountain stages and only one individual time trial after organizers decided to scratch the team time trial from the program.

"We wanted to make sure that anything could happen anywhere," said Prudhomme, who was disappointed by this year's scenario, when all the favorites neutralized themselves for the biggest part of the race.

The first stages of next year's race will pay tribute to two of the most prestigious classics - Liege-Bastogne-Liege and Paris-Roubaix - with riders going through seven cobblestone sectors over a total distance of 13.2 kilometers (8.2 miles) in the third stage between Wanze, Belgium, and Arenberg Porte du Hainaut, France, on July 6. It will be the first time since 2004 that riders will have to handle cobblestones, a difficult task that dashed Spanish rider Iban Mayo's hopes of unsettling Armstrong that year.

"We don't put cobblestones for riders to fall, but to make a selection," Prudhomme said. "There will be 11 kilometers of cobblestones in the last 30 kilometers. There will be some damage."

Following a new feud between the International cycling union and the French anti-doping agency, Prudhomme restated that the fight against doping was his priority.

"This is an absolute necessity," Prudhomme said. "And authorities in charge of this fight need to work together in good terms."

Earlier this month, the French anti-doping agency released a report concluding that teams including Astana had received advance notice of doping tests during the Tour, and that some blood and urine samples were not handled correctly by UCI inspectors. The UCI responded by saying it scrupulously respected the obligations imposed by the World Anti-Doping Code.

On Tuesday, French prosecutors opened a preliminary investigation to examine syringes found during this year's race in a container given by organizers to all the teams in order to collect medical waste.

Asked to comment that case, Prudhomme said he knew nothing about it.

"We learned it from the press," he said.

While there were no positive tests at this year's Tour, authorities did seize drugs that the French anti-doping agency said raised questions. The drugs included treatments for diabetes, high blood pressure and convulsions suffered by manic-depressives.