IN 563AD a tsunami overcomes Geneva. Two accounts of the tragedy, one by Gregory of Tours and the extra by Marius of Avenches, have survived. What caused the wave, and the amount of the damage that resulted, have been matters of assumption for centuries.

But over the past decade numerous groups of scientists have pieced together the order of events and one of those groups, led by Katrina Kremer of the University of Geneva, has now formed a computer model of what happened. Unhappily for the 1million people who live around the lake’s shore, the termination of this research is that something as like could easily happen again.

The huge wave’s tsunami of 563 on track at the opposite end of the lake from Geneva, at the point where it is fed by glacial melt water carried into it by the Rhône. Both financial statements say the wave began with a huge rock fall on what was then called Mount. Tauredunum is thought to be a mount now called the Grammont, which is located near the river mouth.