Located in the northwestern corner of the valley, La Piedra Pintada is a huge boulder adorned with pre-Columbian carvings. Locals sometimes fill in the grooves of the petroglyphs with chalk to make them easier to see. The meaning of the petroglyphs isn’t clear; some think it is an early map of the area. That doesn’t prevent children from giving their interpretation of the petroglyphs for US$2 in Spanish. The stone is about 300m up a trail from the main road.

La Piedra Pintada can be reached by a colorful bus with ‘Pintada’ above the windshield. It passes along Av Central every 30 minutes or so from 6am to 6pm (US$0.25 one way).