How far is 20,000 leagues

Unit Definition (league)
The league became a common unit of measurement throughout western Europe, although its length varied greatly from region to region.

It was originally intended to represent the distance a person could walk in an hour. In many cases it was equal to 3 miles, (note that the definition of a mile also varied from region to region). At sea, the league was often equal to 3 nautical miles, which is 1/20 degree or 5556 meters (metres).

In the USA and Great Britain, the league is defined to be 3 statute miles (~4828.03 meters) on land, or 3 nautical miles at sea.

Unit Definition (mile)
The mile is one of the most common measurements of distance.

It originates from the Latin word for 1000, 'mille'. Originally a mile was the distance a Roman legion could march in 1000 paces. In medieval Britain, several mile units were used, including the modern mile defined as 8 furlongs (1609 meters).

Note that French, Scottish and Iris