It's been an enduring mystery for centuries: How did the ancient Polynesian inhabitants of Easter Island, or Rapa Nui, put those enormous red stone hats on top of the island’s famous giant statues?
In one study, published in 2018, anthropologists photographed the cylindrical hats, known as pukao, and used the photos to make 3-D models they could analyze in depth. Their conclusion? The hats were likely rolled atop the statues using large ramps, in a technique called parbuckling.