Were is the unarmed bobblehead in fallout 3

This is a hard one to find. It is located in a place called Rockopolis. Go to Smith Casey's Garage and head directly west. Look for a rock wall with tattered flags on it. There will be no visible door until you walk up to it. The door will slide open and you can climb down inside. It will be lying next to a body. Good luck. This is the hardest one to find unless you get the perk which shows you all the locations.