The old fundaments from a pulled down building are forming a plane with rubble and patches of weed that tries to survive. An odd feature is that it shows a pattern of fine tracks from an unknown source, possibly snails rasping algae from the surface, but that's a guess [1].
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[1] Move your mouse over photo 2 or 3 to indicate some tracks with arrows. There are many more but they are too small to see.
