Back when the Romans had the only good construction crews in town, it made some kind of sense that every road led to Rome. But in the modern era, how much does that hold up? Roads to Rome is a project that used a combination of OpenStreetMap data and some mapping tools to map the fastest route from a bunch of equally-spaced points, to one focal point.
It was first applied to this map of Europe, which shows the fastest route from 486,713 points to Rome. The more one road was used, the thicker the line, creating the beautiful map you see above.
The same technique was applied to a few other situations, including this map of the US, showing the fastest route from points in the state to state capitals. Although the data isn't particularly useful (highways are faster!), it still makes for a good desktop background.
You can see the full project, along with many more maps, right here.