On formalizing descriptions: @codexeditor this one is harder. It's more difficult to say what something used to be (or anything temporal) with triples. It depicts trenches, but not in the sense of what we would expect to see. it lookslike hills, but that doesn't get it

A great (and moving) example ... It sounds like this could be a case of multiple reference (WWI trenches/modern pits) or of an abstract entity (trenches) which are manifested over time? Although this leaves out territory-over-time, geography, etc.

Yes. The obvious solution here is to create an entity for what used to be trenches during a war, but have become covered with grass, or grown over. A man-made geologic feature of some sort. I have photos of similar looking trenches from the US Civil War.

I have this idea that RDF star helps this problem, but i am not sure how it would work exactly with things like this. cc @pchampin