The Pyrenees National Park covers a mountainous strip of land along the border that is 1-15km wide and 100km long, between the Aspe Valley to the west and the Aure Valley to the east. It takes in six valleys, four of which are in the Hautes-Pyrénées: Arrens, Cauterets, Luz-Gavarnie and Aure. Stopping in at one of the Park houses is a good way to start an excursion full of magnificent waterfalls, lakes with emerald green waters, bubbling sinkholes, lofty and majestic peaks and breathtaking panoramas.