Archaeologists around the world have long unearthed skulls with holes in them. But they were usually dismissed as natural accidents—the result of infections, birth defects, or animal bites. But in 1864 an archaeologist named Ephraim George Squier found a skull in Cuzco, Peru with a hole that was clearly not natural—it was square-shaped. The hole also showed signs of new bone growth around its edge, which meant the person couldn’t have been dead when the hole was cut. This skull was the first unquestionable evidence of something that scientists had long dismissed as impossible—ancient neurosurgery.

Host: Sam Kean

Senior Producer: Mariel Carr

Producer: Rigoberto Hernandez

Audio Engineer: Jonathan Pfeffer

Music:

“Trois Gnossiennes 3,” “Stately Shadows,” “Darklit Carpet,” “Vernouillet,” and “Tossed” by Blue Dot Sessions

“Conjunto Sol del Peru,” by Pockra (Vol. 2: Musica de los Andes Peruanos)

“Conjunto Sol del Peru,” by Wuaylias Tusy (Vol. 2: Musica de los Andes Peruanos)

“Conjunto Sol del Peru,” by Ckashampa (Vol. 2: Musica de los Andes Peruanos)