The term "league" is used for measuring long distance over land and is equal to 3 miles. Just to make things confusing a nautical "league" is a different measurement & is equal to 3 nautical miles or 3.452 miles.
Antarctica is the 5th largest continent and approximately 98% of Antarctica is covered by ice which averages 1 mile in thickness. Predictions on when global warming will lead to ice-less polar regions ranges from 2012-2050. Scientists agree it's not a matter of if, but when.