First, an announcement: Vintage Thingies Thursday has a new home, at the blog of Coloradolady! Thanks for hosting, Coloradolady!
Now, what I have for you today:

I picked up this inlaid wooden box (which is, for some reason, very difficult to photograph) at the bins. It's small--about the size of a pack of cigarettes, or a bit wider--and I originally thought it was a really cool old cigarette case. When I opened it, however:

I found the inside was blue velvet, with a small indentation, as if something should rest there. The first thing that came to my mind was a monacle, as it's about that size and shape, but really, a monacle box? I didn't think much on it, though, as I was very interested by the objects I found inside.

There are two stamps, one American, one Danish. I did a Google search, but couldn't find either of them. I found some 5 cent stamps with Washington on them from the 60s, but they are different than this one. Any stamp folks out there who can help me?
The really crazy thing, though, is the tiny locket. You can't see it very well, due to my poor photography, but it contains two very old looking pictures, one of a man, one of a woman. If my history is right (and honestly, who knows?), the pictures are late 19th century.
What do you think? Any ideas on the origins or timeline of this strange box and its contents?
Editing to add: Thanks to a tip from Coloradolady, if found the US stamp--turns out it is this one, which was made from 1916-1922!