The Pyrenees are famous for the Col du Tourmalet, tour De France and road biking, but they have a great deal more to offer if you know where to look. The French Pyrenees is quickly becoming a Gravel bikers paradise. You only need to zoom in on your google maps to see the vast amount of tracks available to you. 

The Haute Pyrenees Region is perfect and relatively untouched if you want gravel bike adventure.