Unesco World Heritage site Cueva de las Manos features incredible rock art, a must-see if you pass through. Dating from about 7370 BC, these polychrome paintings cover recesses in the near-vertical walls with imprints of human hands, drawings of guanacos and, from a later period, abstract designs. Of around 800 images, more than 90% are of left hands; one has six fingers.
Fundación Flora y Fauna donated an additional 600 hectares to the expansion of Patagonia National Park surrounding it, and will eventually add three new trekking circuits, one with a condorera (condor nesting area), and possibly a campground.
Guides in Perito Moreno and Los Antiguos organize day trips. The trip from Perito Moreno is about 3½ hours (one way) over rocky roads. Once you arrive at the caves, free 45-minute guided walks are given every hour by knowledgeable staff.