Our map uses data from OpenStreetMap something like the Wikipedia of cartography. It's editable - and that's easier than you think! Please help us build the best map of the world inhistory of mankind. And this is how it works:
A) Report an error
Simple: Go to OpenStreetBugs, zoom in to where the error is, and report the "bug". Somebody within the OpenStreetMap will take care of it. (Be specific!)
B) edit the map
Also easier than you think: Go to OpenStreetMap.org, zoom in where you want to edit and click "Edit". You'll need to register (quick & easy). Check the Beginner's Guide for hints.
Remember: No cartographer in the world knows your neighborhood better than you do!