We did two day hikes while in Pays Basque, one in France, the other in Spain. I particularly liked this one in the Valle de Belagua, Spain as it was extremely diverse . The area is just on the border of France and Spain and we had read that there were karst (see wikipedia) formations in the area – so we asked the tourist office if they could suggest any hikes. The person at the tourist office said there were no organized trails and sent us to a cross country ski area and said we should walk the trails. When we got to the area – we couldn’t figure where to go, but across the parking lot was a trail-head so we decided to try it. We were not disappointed.  Photos and videos below: