It is a seven-chamber cave where scientists and experts discovered 67,000-year-old fossilized remains of a Callao man in 2007, that's a thousand years older than the Tabon Man in Palawan. Callao Cave is definitely the top tourist attraction in Peñablanca, Cagayan. This cave is situated on the Northern foothills of the Sierra Madre Mountains. By the way, Peñablanca, the name of the municipality, is a Spanish word that means white rocks because of the limestone present in the area.