The largest circles possible on Earth. You can draw a unique great circle between any 2 points on a sphere (first pass the unique plane through those 2 points and the centre of the sphere; the great circle is the intersection of the plane with the sphere).

Great circles are geodesics, i.e. shortest paths between points. Indeed, ships and airplanes usually travel along great circles.

Log in or registerto write something here or to contact authors.