I've walked past this sign many times but never really noticed it: it's a big, brown Metro sign with the address of the Columbia Heights Metro outside the eastern station entrance. And that's it. It's sort of beat up and doesn't look like the rest of the canopy, which is quite nice.
Seems strange -- who sends mail to the Metro, other than Metro? Why not just put some plaque on the canopy itself, or the concrete wall there?
The mysteries of our neighborhood.