Castle of Ancient Kingdoms
It's just a blockwaved black and white engraving from an old book about Columbus. Or to be precise; it's a detail of the blockwaved image.
The full image is just below here. The above is a detail from it. Feel free to explore like I did, although this sort of imagery may not appeal to everyone.
Click here to view the huge original (4540px x 5840px, 604k)
If you look at the original blockwaved image as a thumbnail, it just looks like a blurry image of the original engraving. I find this quite intriguing as it's the tiny details that are interesting and in fact, that's all the blockwave filter has actually changed.
You can see similar effects in something like ASCII art where a picture is made up of letters and is actually a text file and not an image file. The image looks perfectly normal from a distance, but up close it appears to be made of tiny insect characters, in other contexts commonly referred to as letters and numbers.
If I was writing an encyclopedia or just plain trying to promote myself and sound important and original, I would refer to it as a whole new genre call something like, "Micro-Art" (it's too small to be two complete words, so I hyphenated it).