The sanatorium in Nazca was a medical facility for the long-term ill and mentally ill of Nazca, Peru. Dedicated to Saint Anthony de Padua, it was housed in a large adobe building with barred windows, and was run by nuns.
When Harold Oxley wandered into Nazca, having been driven mad by the Crystal Skull of Akator, he was taken to the sanatorium, and given his own cell. While he was there, Oxley carved images of the crystal skull and the word "Return", translated in many languages, into the walls of his cell. He also carved a map of the Chauchilla Cemetery into the floor of his cell. Eventually, he was taken from the sanatorium by men with guns, likely Soviet agents.
Several months later, in 1957, Indiana Jones and Mutt Williams went to Nazca guided by a riddle in a letter by Oxley, inviting them to follow the lines only the gods can see. After their arrival, they learned that Oxley had been at the sanatorium. When they arrived there, Sister María told them what she knew about Oxley's arrival and departure, and guided the pair down the hall past a fast speaking inmate and a shouting inmate to Oxley's abandoned cell, and let them in. Inside, Jones and Williams realized how deranged Oxley had become, and began examining the carvings he had left behind. Realizing that Oxley had been obsessed with returning the skull, they searched for clues, and Jones realized in the riddle, "Orellana's cradle" could also mean "Orellana's resting place", and then found part of the map on the floor. Getting Williams to sweep up the dusty floor, Jones climbed up against the windowed wall, and saw the map of the cemetery where Oxley had found Orellana's burial site. The two set off to find where the cemetery was located, unaware that they had been followed to the sanatorium by George McHale.