Today, many planes fly over the Arctic using "great circle routes" between the continents. The great circle route (picture) between Chicago and Hong Kong passes over the Arctic Ocean and near the North Pole (Marked: + ).

A "Great Circle Route" is a trace on the surface of a sphere (the Earth) of a plane that passes through the center of the sphere and divides it into halves. This line indicates the shortest course between two points on the surface of that sphere.

The lines of latitude and longitude on a flat map may suggest otherwise, but when you take into consideration that the Earth is round, the best route can be a surprise. Before long-distance air travel, such efficiency was not possible - try sailing over land or through the frozen Arctic Ocean!

Imagine picking two points (A and B) on a round melon. When you cut it, the top of your knife will stop at A, the bottom of your knife will stop at B, and the center of your knife will be aligned with the very center of the melon. The cut mark will indicate the shortest distance between A and B on the skin of the melon.