This cool and dense swathe of jungle, officially called Mandala Wisata Wanara Wana.
The sanctuary is inhabited by a band of grey-haired and greedy long tailed Balinese macaques who are nothing like the innocent looking doe-eyed monkeys on the brochures. They are ever vigilant for passing tourist who just might have peanuts and ripe bananas available for a quick hand-out.
The interesting Pura Dalem Agung is in the forest and has a real Indianan Jones feel to it. Look for the Rangda figures devouring children at the entrance to the inner temple.
(reference lonely Planet)