I think everyone at some point has owned a Viewmaster. It was a bright red handheld viewer for looking at stereoscopic images.
The Viewmaster discs had small images around the outside. When you inserted a disc into the top of the viewer, two almost identical images aligned with your left and right eyes, giving the impression of 3D-ness. You changed the image by pulling a lever down with your right forefinger, which rotated the disc to the next set of images.
I think I got my first Viewmaster when I was 6, along with a few sets of discs. The demo discs had some superb images on them – one was a NASA rocket, an underwater scene, and I seem to remember a Grand Canyon picture too. When you removed the viewer from your eyes, there was also a caption about brow height that changed with the images, explaining the scene of giving you a brief commentary.
In the mid 80s I received another Viewmaster, although I can’t remember why. It might have been a Christmas or birthday present or I might have stolen my sisters, I genuinely don’t know, I just know that I ended up with more Viewmasters than I could practically use at once.
Then when I got married years later, I discovered that my wife also had a Viewmaster. She also had a load of discs that I hadn’t seen before. From that point on, it was obviously a match made in heaven.