On the surface, the Kukulkan temple that sits among the ruins of Chichen Itza looks nothing like a Russian nesting doll, but it's essentially the pyramid equivalent, according to scientists.
Perhaps unbeknownst to the 1 million people who annually visit Chichen Itza, the "new" world wonder in Mexico's Yucatan state, the 100-foot-tall structure—built between 700 and 1,000 years ago—actually sits on top of a smaller, 65-foot-tall pyramid built up to 200 years earlier and discovered in the 1930s, per the BBC.
In the 1940s, an archaeologist reportedly made mention of the possibility of another structure beneath the others, and a third pyramid is exactly what scientists found during a recent scan.
Hence the Russian nesting doll comparison: "Under the large one we get another and another," says project head Rene Chavez Seguro. This newly discovered pyramid, reaching 33 feet tall, may be up to 1,500 years old and appears to have a staircase and an altar at its peak.
It's also slightly out of alignment with the other two pyramids, which "may indicate that there are other buildings hidden at the same level," reports Deutsche Welle.
As for why the Mayans built over it, the BBC cites two possibilities: a transfer of leadership or because it was simply in bad shape. CBS News reports the discovery was made using a non-invasive electrical imaging technique called 3D Electrical Tomography, and says no excavation plans have been announced.
(This Mexican "mountain" is actually a stack of six pyramids or more.)
This article originally appeared on Newser: Inside the Pyramid Is a Pyramid. Inside That Is Something More
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