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 Manitoba Lake. It also was part of the route of the fur trade to Hudson Bay. The name derives from Cree "manitou-wapow" or Ojibwa "manidoobaa", both meaning "straits of Manitou, the Great Spirit", a toponym referring to what are now called The Narrows in the centre of the lake. These narrows were an area that the spirit could be heard. What exactly was heard, and in what exact location, seems to be a mystery. The lake was known to French explorers as "Lac des Prairies". The short-lived Republic of Manitobah and its successor the province of Manitoba both take their name