Qoyllur Rit’i, the annual sacred festival held in the high Andes Mountains of Peru at the foot of Mt. Ausangate, in the Valley of Sinakara, is probably the most important festival of the year. It combines a dangerous moonlit trek to what remains of a melting glacier in an ancient Andean ritual of renewal by sacred Apu waters with the Roman Catholic ritual of the Mass, celebrating the Lord of the Snow Star. The fiesta runs three days and nights without pause. It is an exhausting cacophony of noise, a riot of costume, and a spectacle of movement. Part of the festivities include dancing and dressing up as various mythological or historical figures each wearing their uniquely identified costumes. One of these groups, the Qollas, dress in this mask with a hat, a woven sling, and llama skin and represent the Aymara residents of the Altiplano region of the Andes mountains. Another group, called the Ukukus, or bears, also wear this type of mask.