Peña Roya beech forest, Moncayo Natural Park, Zaragoza, Aragon, Spain (© David Santiago Garcia/DEEPOL by plainpicture)

Spain's Aragon region isn't exactly famous for its forests—it's more 'sun and scrub' than 'shade and shuffle.' And yet, climb the slopes of Moncayo and you'll walk straight into a twist ending: a dense, whispering beech forest. The mountain is a climate roller coaster. At the bottom? Mediterranean shrubs. Midway up? Oaks and pines. Push further? Suddenly you're in Peña Roya, a beech wonderland that seems to say, 'Surprise, leaf it to me!'