Enjoy some time out from concrete and cities at Quill Lake. This is an ideal place to fill your lungs with fresh air, slow down and soak up the views.
You'll be spoiled for sightseeing choice when spending time in Northwest. Quill Lake is a good place to begin here, but there are lots of other fine places to experience. White House, Arlington National Cemetery, and Lincoln Memorial are close to the body of water and will fill in your day nicely.