One of South America’s finest examples of rock art, Cueva de las Manos (peritomoreno.tur.ar) has been dazzling visitors ever since an Italian explorer first wrote about the site in 1941. Set in a deep canyon amid the arid Patagonian Steppe, the "Cave of the Hands" is a collection of rock shelters and overhangs covered with eye-popping paintings made over 9000 years ago. These polychrome paintings adorn 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.
In the area, you might also see guanacos, Andean condors and cuis – the small diurnal rodent common to this region. Visits are by guided tour, which happens hourly (typically between 9am and 7pm in the summer, with a shorter winter schedule). You'll don a helmet and spend an hour or so walking around this incredible prehistoric gallery, while learning a bit about the people who created it – though many mysteries remain.
Reserve tickets ahead online; the tourist office in Perito Moreno can help if you have trouble with the website.