There are also really odd things like streets that seemingly dead-end, but which actually continue in the same direction but offset by one or more blocks; in other words, a street that takes a dog-leg via a crossing street. The problem is that there are almost never signs to tell you which way to turn to stay with the street you're on, or even that the street does, in fact, continue.

Even with a GPS, DC can be hard to navigate because there are so many discrepancies between most map databases and the actual streets. For example, I have a relatively recent Garmin, and every time I'm in DC it tries at least once to turn me the wrong way down a one-way street, or tries to send me down a street that isn't there. The one-way streets aren't alternated logically like the ones in NW Portland, either; there may be some rhyme or reason to the one-ways, but I have yet to decipher it. Another experience I often have in DC: a street I'm on suddenly becomes one-way in the opposite direction.