Today on Google's home page, worldwide, is a special interactive Google logo, aka Google Doodle for the 194th birthday of Léon Foucault. Featured is his Foucault Pendulum, which was used to demonstrate the rotation of the earth in 1851.
Leon Foucault was born on September 18, 1819 and died on February 11, 1868 at the age of 48 in Paris, France. It is believed he died from a rapid case of multiple sclerosis.
The Google Doodle has an interactive logo that lets you virtually play with the Foucault Pendulum. Here is an animated version of this logo:
To learn more about his life, see his Wikipedia page.