This is what may have happened around 3,200 BC on the Lake of Mondsee (Lake Constance), resulting in the exodus of a metalworking community that lived there. When the site of this particular settlement was excavated in the 19th century, 595 stone axes and studded battleaxes, 451 arrowheads along with 12 copper axes and six daggers were discovered. These items represented highly sought-after status symbols, and would never have been left behind intentionally, unless of course the settlement had been abandoned as the result of a disaster. Well preserved foods such as charred hazelnuts, grain and pieces of apples were...