Lake Geneva to swim at some beaches of the lake; indeed, visibility under water was near zero. By the 1980s, intense environmental pollution (eutrophication) had almost wiped out all the fish. Today, pollution levels have been dramatically cut back, and it is again considered safe to swim in the lake. Major leisure activities practiced include sailing, wind surfing, boating (including water skiing and wakeboarding), rowing, scuba diving and bathing. On a scientific footnote, in 1827, Lake Geneva was the site for the first measurement of the speed of sound in (fresh) water. French mathematician Jacques Charles François Sturm and Swiss Physicist Daniel
Lake Geneva than in Geneva. In 563, according to the writings of Gregory of Tours and Marius Aventicensis, a tsunami wave swept along the lake, destroying the fort of Tauredunum and other settlements, and causing numerous deaths in Geneva. Simulations indicate that the Tauredunum event was most likely caused by a massive landslide near the Rhône delta, which caused a wave eight meters high to reach Geneva within 70 minutes. In 888 the town was part of the new Kingdom of Burgundy, and, with it, was absorbed into the Holy Roman Empire in 1033. In the late 1960s, pollution made it dangerous