A new theory is that a 1,000-year-old wall in Peru was intended

in Interview with LiveScience Science Media One of the researchers behind the find, University of Florida archaeologist Gabriel Prieto, says the wall served as protection against heavy floods.

Flood deposits on the eastern side of the wall indicate that the work protected farmland and valuable canals from flooding caused by El Niño.

El Niño returns about every three to five years, when the sea temperature off the coast of Peru rises, causing a drop in atmospheric pressure in the area.

This brings heavy rainfall in South America. And in these usually dry areas, heavy rains often trigger devastating landslides and mudslides. 1,000 years ago, deposits in the Muralla La Cumbre show.

“The annual amount of precipitation in a typical year is very low—almost no rain at all,” Gabriel Prieto explains to LiveScience.

“So when it was raining really hard, it caused a lot of damage.”

It may also have a protected capital

When Gabriel Prieto and his group began studying the 2.5-meter-high wall, they only discovered remnants of flood deposits on the eastern side.

Therefore, it appears that the wall was also constructed to protect the Chimo farms to the west.

In addition, the research team carbon-dated the lower layers of the wall, revealing that the wall began building around the year 1100 – likely after a large-scale El Niño flood.

The wall is built on the course of the Gavin River, which floods when heavy rains. Thus, the wall also acts as a kind of dam builder, Prieto explains.

In addition to protecting agriculture, a network of canals indicates that the capital of the Chimur Kingdom, Chan Chan, was protected at the same time.

The research group’s findings are now subject to peer review. However, independent researcher Edward Swenson of the University of Toronto accepts LiveScience Gabriel Prieto’s theory.

“The idea seemed nonsensical to me at first, because I’d never heard of waterproof walls,” he says.

After Prieto’s new findings, he becomes convinced that the wall was protection against floods, but he insists it was also a defense against Inca attacks.