There are thousands of aligned holes in Peru. Archaeologists now think they know who created them

(CNN) — A series of about 5,200 holes stretching nearly a mile (1.5 kilometers) across the Pisco Valley in the southern Peruvian Andes has baffled researchers for nearly a century. But a fresh look at the site, called Monte Sierpe, or “serpent mountain,” may help archaeologists to decipher why ancient people constructed it hundreds of years ago.

The “band of holes,” as it’s informally called, first garnered attention when National Geographic published aerial photos of the site in 1933.

But there are no written records relating to the formation, leaving its purpose open to interpretation — and there have been many. Hypotheses about the holes’ use have included defense, accounting, storage, gardening, water collection, and fog capturing purposes. People who support ancient astronaut theor