there are those mysterious remains of some ancient fortification in Otzenhausen, near Trier.
https://en.wikipedia.org/wiki/Celtic_circular_wall_of_Otzenhausenhere in Finland we have like nothing, since old stuff was either built by Swedes to fortify against Ruskies, and anything build before that has disappeared ages ago. (common building material; rotting/burning wood)
When Egypt built pyramids, we were kinda just getting away from ice age...