OK, I have a new fun one for this thread. Fun for me.
I was reviewing a locomotive in the loco cat and this particular engine was similar to another
I had posted a waymark for in Roseburg Oregon. I have some personal family history related to this locomotive so I like it for that reason already but it is one of only ten of that particular style in existence so it is eve a bit more special in my mind based on that. So since it was similar I thought I would do a quick check to see if it was from that same particular group of engines. This led me to Google the engine number and rail line and included in the results that were returned was a site that had stolen my photo for a blog post. I posted about that elsewhere so won't rehash the plagiarism aspect here.
The blog entry was about a Buster Keaton movie. It's most famous shot featured a steam engine numbered 1229 just like the one I had posted here. So I looked about and low and behold I verified that it was the same engine. Of course it has had some changes in the last 89 years when the movie was shot but the bolt patterns on the front of the boiler match on my high resolution photos and the number plate is exact.
I was able to find the film at the Internet Archive and there was also a clip of the particular scene already on YouTube. So I thought I would try a film location waymark. Now the film was shot in California but the location of this shot featured the front of the engine that is now in Oregon so I was unsure how high it would fly but it was returned approved and is my new current favorite....and to think I would have never known except for a stolen photo.

Waymark:
SP Locomotive #1229, "The Goat"