Find the shortcut
Three routes are drawn on the map between two airports. Which one is really the shortest?
How to play
Two airports, three coloured routes. Pick the one you think covers the least distance. After you choose, each route shows its true length in kilometres.
The surprise
The shortest path between two places on a globe is a great circle. On a flat map it looks curved, and a dead straight line on the map is usually longer. That is why flights from Europe to North America bend north over the Atlantic.
Difficulty
Easy compares the shortest route with two obvious detours through other airports. Medium adds the straight line drawn on the flat map. Hard uses routes that differ by only a few percent.
About the distances
Lengths are calculated along each drawn path using great-circle segments between points. Real flights are affected by winds and airspace, so this is geometry, not a flight plan.
Difficulty and modes
Easy, Medium and Hard each have their own puzzle every day, so there are three to play. A tick on the tab means you have finished it. Unlimited is endless survival play at the difficulty you choose: keep going until you slip, and try to beat your personal best, which is saved in your browser.
More games: Longer Flight, Route Ranking, Code Quiz, Plane Spotter, Population Match, Border Run, Pinpoint, Antipode, Mystery Country, Flag Mixer, Outline, Neighbour Rush, Capital Hunt, Shortcut, Population Showdown, Overflown.