Short answers, pulled from the story.
The French government declared the litre in 1795 as the volume of a cube measuring ten centimetres on each side. This definition linked the unit of volume directly to the unit of length during the French Revolution.
The General Conference on Weights and Measures redefined the litre in 1901 as the volume occupied by one kilogram of pure water at its maximum density. This definition persisted until 1964 when the original geometric definition was restored.
The General Conference on Weights and Measures adopted the uppercase letter L in 1979 to distinguish the symbol from the handwritten digit one. This change prevented frequent errors in reading and writing measurements in English-speaking countries.
In many European countries, the centilitre is the standard measure for drinking glasses and small bottles with common sizes being 25 cL, 33 cL, and 50 cL. The United States rarely uses the centilitre and prefers the millilitre and the litre instead.
The litre became exactly equal to one cubic decimetre in 1964 when the original geometric definition was restored. This correction resolved the discrepancy that existed for sixty-three years between the mass-based and volume-based definitions.