The Aletschhorn is a mountain in the Alps in Switzerland, lying within the Jungfrau-Aletsch region, which has been designated a World Heritage Site by UNESCO. The mountain shares part of its name with the Aletsch Glacier lying at its foot. The Aletschhorn, the second highest mountain of the Bernese Alps after the Finsteraarhorn, is the only one of the higher peaks that lies completely in Valais.