Twenty Thousand Leagues Under the Sea
By: Jules Verne
Twenty Thousand Leagues Under the Sea (French: Vingt mille lieues sous les mers) is a classic science fiction novel by French writer Jules Verne published in 1870. It tells the story of Captain Nemo and his submarine Nautilus as seen from the perspective of Professor Pierre Aronnax. The first illustrated edition (not the original edition which had no illustrations) was published by Hetzel and contains a number of illustrations by Alphonse de Neuville and Édouard Riou.
The title refers to the distance traveled under the sea and not to a depth, as 20,000 leagues is over 15 times the radius of the earth. The greatest depth mentioned in the book is four leagues. A literal translation of the French title would end in the plural "seas", thus implying the "seven seas" through which the characters of the novel travel. However the early English translations of the title used "sea", meaning the ocean in general, as in "going to sea".
The word leagues in the English title is a literal translation of lieues, but refers to French leagues. The French league had been a variable unit but in the metric era was standardized as 4 km. Thus the title distance is equivalent to 80,000 km (twice around the Earth) or roundly 50,000 statute miles. In common English usage 1 league equals 3 statute miles. (Source : wikipedia)