Nerval's Lobster writes: "What's the most optimal path for Santa (if he actually, you know, existed) to travel around the world on Christmas Eve? The answer is a variation of the classic "Traveling Salesman Problem." According to a history of the problem compiled by Georgia Tech, the traveling salesman problem (or “TSP”) dates back to the 1800s, when Irish mathematician Sir William Rowan Hamilton challenged friends to navigate 20 points in the shortest path using only a series of specified connections. But it wasn’t until the first decades of the 20th century when statisticians began to tackle the challenge in a more systematic way. The World TSP Problem involves 1,904,711-city instance of locations throughout the world, with a most-optimized route of 7,515,778.188 kilometers (4,670,090 miles). The "Santa problem" would be even more complex — hope those reindeer are well-fed." Link to Original Source
One of the chief duties of the mathematician in acting as an advisor...
is to discourage... from expecting too much from mathematics.
-- N. Wiener