Be careful, since yesterday, June 19th, the descent to Rivèrenert has been freshly graveled and dangerous. I had a rear puncture due to small, sharp gravel sticking to the tire when braking. So, don't go crazy on this descent, friends.
Couserans is a Gascon country of mountains, hills, meadows, lakes, waterfalls and forests which is entirely part of the Pyrénées Ariégeoises Regional Natural Park.
The Col de la Core, at 1,395 meters above sea level, is part of both the pass route and the GR10 which cross the Pyrenees from the Atlantic to the Mediterranean.