Damn, where to start. I found some wreckage to an old WWII type bomber in Oregon. Just bits and pieces of aluminum, and most of an old radial aircraft engine.
An old VW Bug in the middle of a forest. I have no idea how it got there, I couldn't get there in my Blazer, either the bug was driven there before the fifty foot trees were planted around it, or it was dropped from an airplane or chopper.
Found an old fallout shelter in the mountains in So Cal, two steel doors, and two ladders leading down to a large concrete room. I salvaged a table and two chairs from it which I still have.
Last month I found two old guns laying out in the desert in West Texas. The first was a Reminton single shot rifle, the other was a J Stevens single shot shotgun pistol. The wood on the rifle was rotted away, but the metal parts aren't bad. I was able to clean the pistol enough to break it open and get the hammer and trigger to work, but the firing pin is still stuck tight.
I also found several belts of .50 cal ammo and two horse skeletons in the same general area as the guns.