Piedra de San Martín is a drive worth taking
Piedra de San Martín, or Col de la Pierre Saint-Martin, is a high mountain pass at an elevation of 1.760m (5,774ft) above the sea level, located on the France-Spain border in the western Pyrenees in the department of Pyrénées-Atlantiques (France) and Navarra (Spain).
The road to the summit is totally paved. It's called D132 (France) and NA1370 (Spain). La Pierre Saint-Martin is ringed by contrasting lands and scenery, rendering each climb up the pass a unique journey. The pass has been climbed by the Tour de France bicycle race. At around 20km it is long and has a very hard section in the middle. It is not as hard as Tourmalet or Hautacam but it can rival them for spectacular scenery.
There are 2 routes to reach the summit. On the West side (from La Caserne), the climb is 18 km long, with an elevation gain of 1.320 meters. The average gradient is 7.3 % average gradient. On the North side (from La Mouline), the climb is 18.5 km long with an elevation gain of 1305 meters. The average gradient is 7.1 %.