Spanish council workers in the town of Cristovo de Cea destroyed a 6,000-year-old Neolithic tomb after mistaking it for a broken park bench and replaced it with a white picnic table.
The workers in the Galician town destroyed the slabs of the tomb of ancient Celtic settlers and filled in the ancient burial chamber with concrete. An archaeologist called the action a "monumental error".
Local environmental group Grupo Ecolozista Outeiro reported the destruction of the tomb.
"The rolled concrete and modern picnic bench have caused irreparable damage, replacing what was a prehistoric cemetery of the first inhabitants of Cea..." the group wrote in a complaint to Spanish prosecutors, reports The Local.
Authorities claimed they were not aware the site was archaeologically significant. "No one told me, neither Heritage nor the environmental group," the town's mayor, José Luis Valladores told the Spanish Huffington Post. "The site wasn't even marked, and the logical thing would have been for them to get in contact with the local council so that we could have taken measures to protect the site," he added.
No-one though seems prepared to shoulder the blame, with a spokesman for Galicia's Department of Culture, Education and Universities saying it had authorised archaeological work to take place in the town in 2008, and town authorities were aware of the site's existence.
Archaeologist Juan Barceló, professor of prehistory at the Universitat Autonoma of Barcelona, called the destruction of the tomb a "monumental error".
"Probably because it was the summer holidays, the local authority was not available and someone with no knowledge of the local heritage decided to act on their own," he told The Local.