The 2007 Tour de France is imploding. The teams sponsored by Astana and Cofidis, based on the positive drug tests of one rider from each squad, have withdrawn.

Michael Rasmussen of Denmark, the leader of the race since stage eight, has been kicked of the event by his team, Rabobank, for lying about his whereabouts for out-of-competiton drug tests.

But until further notice, the race will go on. And as such, there are four stages left in the race's 94th edition, including a rolling voyage Thursday from Pau to Castelsarrasin.

But who knows how the remaining riders will react to the latest catastrophe?

If they continue to ride, it will be 188.5 kilometers (117.1) miles on a day, if riders are still racing aggressively, could feature attacks by those seeking a single-day spotlight.

The stage will include six categorized climbs, none of which will prove substantially challenging. The climbs' details:

Km 23: Côte de Baleix, 1.4 km climb,  8 percent average grade, category 3
Km 54: Côte de Villecomtal, 3.7 km climb, 4.3  percent average grade, category 4.
Km 59.5: Côte de Miélan, 1.4 km climb, 5.4 percent average grade, category 4
Km 63.5: Côte de Sa
inte-Dode-aux-Croix, 2.0 km climb, 5 percent average grade, category 4.
Km 72.5: Côte de Theux, 1.4 km climb, 6.4 percent average grade, category 4.
Km 169.5: Côte de la Montagnère:, 1.4 km climb, 5.3 percent grade, category 4.

As a Tour start or finish city, Pau has been part of the race nearly 60 times since its debut in 1930. Fausto Coppi of Italy won in 1952; Bernard Hinault (the last French rider to win Tour) won a stage to Pau in 1979; and German Erik Zabel was victorious in a finish to Pau in 1997.

Tour departure cities get the benefit of a lot of pre-stage introductions, a grand depature village and a lot of race promotion. Then the race abruptly leaves town.

For stage 17, the departure in Pau could be more significant. With the departure of two teams and the race leader, Tour organizers will likely have a lot to say at the start. The cyclists, the media and the public will also more than likely be active participants in the scandal the Tour has become.

If the race continues, the field will progress through the Armagnac region west of Toulouse, with a flat final 40 miles en route to Castelsarrasin

A Tour stage has never concluded in Castelsarrasin, but finishes have occurred in nearby Montauban (1998) and Valence d'Agen (1978).

In 1998, Jacky Durand of France outsprinted five others who arrived nearly eight minutes ahead of the field in Montauban. Twenty years earlier, the stage to Valence d'Agen voided when riders protested logistical problems, stopped en masse and walked with their bike the final 100 meters and across the line.