Last year, archaeologists using electrical imagining techniques found that the pyramid, which is also known as El Castillo, was built atop a subterranean river, or a cenote.
Archaeologists have long known that a smaller pyramid is encapsulated underneath the visible temple.
Researchers said Wednesday that they had detected an even smaller structure inside the other two structures. Using what is called tri-dimensional electric resistivity tomography, or "ERT-3D," they found a 10-meter (yard) tall structure within the 20-meter (yard) tall 'intermediate' pyramid that was covered over by the last construction stage, perhaps around 900 A.D.
Archaeologist . . .
