For a hair-raising but rewarding cycle – if you have experience and good bike-handling skills – take a colectivo (S10) up to Paso de Portachuelo (4767m), east of the Lagunas Llanganuco, and cycle back down. The unpaved road has enough twists and turns to make you dizzy (if the altitude doesn't) and will deposit you back in Yungay after three to four hours. Bicy-Centro in Yungay or Pony Expeditions in Caraz rent bikes.