2 Best Sights in The Pyrenees, Spain

Take a breathtaking riverside hike (1½ hours) on the Ruta de las Pasarelas loop, which hugs near-sheer cliffs that plunge into rushing turquoise waters. There's a waterfall, a cave, and plenty of placards with information on the surrounding nature and historical buildings. Be sure to bring plenty of water and to arrive early, since parking (follow the signs) is limited. Certain stretches are on metal pathways with steep drops, so those with limited mobility or a fear of heights should skip this one. The trail starts at Plaza de Rafael Ayerbe beside the ayuntamiento (town hall). No bikes or pets are allowed.

With a trailhead at the ski area of Núria, at an altitude of 6,562 feet, the dramatic—and occasionally heart-stopping—"engineers' path" is best done in summer. The three-hour trek, aided at one point by a cable handrail, leads to the remote highland valley of Coma de Vaca, where a cozy refuge and hearty replenishment await. Call ahead to make sure there's space, and check weather conditions. In the morning you can descend along the riverside Gorges de Freser trail, another three-hour walk, to Queralbs, where there are connecting trains to Ribes de Freser.