If you're looking for a way to waste time at the office, look no further than Andrei Kashcha's City Roads project. Using OpenStreetMap, the website lets you enter any town or city in the world and generates a map of all the streets within the city limits, from New York City to Norilsk (in Siberia).
The map shows off the differences between cities with a certain amount of urban planning (see: Philly) compared to those that grew willy-nilly (see: Boston):
Urban planning lessons aside, the tool is also just an excuse to look at some cool cities. Here's Tokyo:
And here's Rome, where the old city walls are inescapable:
Or you can stress yourself looking at Los Angeles' freeway system:
Remember how London's taxi drivers have to remember all the city's streets before they can start the job? About that:
The site lets you customize the colors and save any city map as a PNG image, so go wild and make yourself some screensavers. Or just spend the whole afternoon trying any cities you can think of, which is, uh, definitely not what we're planning to do.