They probably won't... but maybe... https://en.wikipedia.org/wiki/Mound_Builders
Nowadays archaeologists also trying to figure out what role each thing they found already played in ancient society.
Nobody really don't know why (and how) Egyptian pyramids built in such form as we know it now.
Every thing in our life is a game; Just remember that each player in real world has only "1 life" & there are NO "god mode", even more — there are NO objects which could grant user at least "1UP".
[Spoiler] «The Game of Life». RIP John Conway[0]
This one almost certainly won't stay there. None of them will. But whatever gets preserved will be some crazy stuff that future people have no chance of understanding.
(But well, nobody should be surprised that our civilization can align things with the true North... So, nobody probably will.)
(I know the dirt walls won't last a decade, don't ruin my fun.)