Le Tumulus de Sables

At https://phys.org/news/2019/05/mysterious-ancient-burial-mound-years.html … the burial mound of Le Tumulus de Sables was discovered by chance in 2006 – in the playground of a kindergarten. The burial mound, located near Bordeaux, was in use between 3600 and 1250BC, a remarkably long time. The mound itself is unremarkable – not on a hill or at an obviously significant location. The site must instead have had something else that was special about it – but it is not known what. People were being buried in it over 2000 years – and long after other such burial mounds went out of use. The research is published in the Journal of Archaeological Science: Reports (May 2019)