Return to sender?
I'm usually not a fan of first day covers and other, "philatelical market oriented" covers, especially if they are not even addressed to someone, which nowadays seems to be the preferred way to collect that stuff. The FDCs in my day at least had your address on and were actually sent to you via the post. But hey, when writing articles and looking for illustrations, I sometimes have to swallow a little and go for stuff I normally wouldn't buy. And this one here is one of those items.

And I must say, as far as such covers go, it is a very nice one. And the point it makes, and that's why I was glad to have stumbled upon it, is that that beautiful stamp was not merely issued for the Queen's visit to Canada, but that the visit was made with the purpose of opening the St Lawrence Seaway, which is what my article is about. The cover links the two events more than the stamp itself does. I had already managed to get a nice block of the stamps

which I would have used with an accompanying caption, but now I have this lovely cover that says it all. So I'm chuffed!