The world’s oldest artwork, believed to be at least 40,800 years old, was discovered in the Cave of El Castillo, literally, “the cave of castles”, near the town of Puente Viesgo, about 30 kilometers south of Santander in the Cantabria region of what is today Spain. The cave and its artwork was discovered more than a century ago but the paintings couldn’t be properly dated using traditional methods such as radiocarbon dating because of the absence of organic pigment. A couple of years ago, a team of archeologists dated the thin layer of calcite formations that developed on top of the art using radioactive decay of uranium and arrived at an astounding figure of 40,800 years, making it the earliest known example of prehistoric art.

The caves of El Castillo contain more than 100 different images painted in charcoal and red ochre on the walls and ceilings of multiple chambers. There are pictures and outlines of animals and club-shaped figures but most are simple hand stencils and red disks created by placing hands on the wall surface and blowing paint on top of it. But are those human hands?