From a plaque by the mural:
Painted in 1977, A People Without Murals is a Demuralized People is the oldest and only mural remaining in Adams Morgan created by a group of Latino immigrant artists. It was brought back to life in 2005 by Sol & Soul, A D.C. Artists-activist organization, with the collaboration of artist Juan Pineda.
I worked only a few blocks away from Un pueblo sin murales es un pueblo desmoralizado... in the early to mid 2000's and don't remember coming across it, but this was before the restoration work began. Wish I had.
Due to urban placement, coords are approximate; once you see the mural you'll need to rely on your geosense more than your GPS. Please remember to replace just as found, and don't forget your writing utensil -- enjoy!
** Congrats to white-star and hutchjth for the FTF! **
UPDATE 5.20.2012: Dropped by to replace the log and was saddened to see the state of this mural. The parking lot attendants say the recent earthquake left many cracks in the building wall, the patching of which resulted in the severely degraded mural. It's been restored once, hopefully this beautiful and historic mural will be so once again.
UPDATE 4.10.2014: Great news, the mural is now undergoing restoration! Can't wait to see it returned to its former glory.