So I hereby nominate the "group performing a ritual" who may have permanently disfigured some of the greatest works of art on our planet, the Olmec heads of Tabasco.
"This act was carried out by persons performing an apparent ritual," the institute said. "As part of the 'ceremony," they poured oil, grape juice, salt water and other substances" over the heads, a tomb, altars and other structures.
Grape juice and oil?? WTF??
"The Aztecs and Mayas daubed ceremonial structures with the blood of human sacrifice victims. But pouring substances like grape juice and oil over statues does not figure in most historical accounts of pre-Hispanic religions."
These pieces are displayed in an awesome open air park in Villa Hermosa with howler monkeys in the trees. It was one of our favorite places in Mexico.
On a side note, the Olmec produced a variety of terrific art beyond the giant heads including awesome jaguar and human/jaguar mixes and cool miniature tableaux.