Free Tourist Map Of D.c. Where Can I Find A Good Tourist Map Showing The Sites?

Where can I find a good tourist map showing the sites? - free tourist map of d.c.

Hello, I am in London within two weeks and have an afternoon and evening free for sightseeing and a couple of hours to complete the next morning. Come along on a trip in the morning, which means that we watch most of the major sights, but we have free time, others we prefer to look at ourselves.
Where can I find is a good map with the locations to read and fairly easy to follow? If possible, also in printed form? Thank you in advance for any reply.