BARCELONA: The seventh stage of the Tour de France between Barcelona and the Andorran ski resort of Arcalis has started, with Lance Armstrong facing his first big test in the mountains.

The 139-mile stage — the longest on the Tour this year — features the category 1 Col del Serra-Seca before the climb to Arcalis, which is classified "beyond category." The final ascent is 6.5 miles long and has an average gradient of 7.1 percent.

Armstrong is second overall, just a fraction of a second behind leader Fabian Cancellara of Switzerland, and nearly all his rivals are lagging far behind except for teammate Alberto Contador of Spain, who is just 19 seconds back and is regarded as the best climber in the world.