Sautuola’s first reaction was to laugh, but quickly he became “so enthusiastic,” Maria recalled, “that he could hardly speak.” He gradually convinced himself that the paintings really were ancient (the latest studies suggest some are more than 25,000 years old). Back in 1879, though, no one knew this. In fact, when Sautuola presented the site at the International Congress of Anthropology and Prehistoric Archaeology in Lisbon in 1880, the professionals laughed him off the stage.
