Caverna de Las Brujas is a magical limestone cave on Cerro Moncol, 72km south of Malargüe and 8km north of Bardas Blancas along RN 40. Its name means ‘Cave of the Witches.’ The cave complex stretches for 5km. Guided tours (admission and flashlights included in the price) take two to three hours. Tours depart with a minimum group size of two, although getting more people together will bring down the per-person cost. Check with tour operators in Malargüe for details.