For unknown reasons, the Cucuteni-Trypillian culture used to burn down their settlements every 75-80 years: https://en.m.wikipedia.org/wiki/Burned_house_horizon

For unknown reasons, the Cucuteni-Trypillian culture used to burn down their settlements every 75-80 years: https://en.m.wikipedia.org/wiki/Burned_house_horizon https://en.m.wikipedia.org/wiki/Burned_house_horizon