Not land art – Clue

I am succumbing to the recent trend of old style GE puzzles. And this is a kind of "what are those?" puzzle too, except maybe it isn't hard to guess (I think).

GE/GM, not too revealing please.

An early clue for this one. Apologies too. I thought it was feasible. It only goes to show that a puzzle we post may seem easier than it really is for those who don't already know the answer...

SPOILER: Click to show

This is at the same place and maybe it will be a little less hard to indentify what "those are".

And the one you're looking for is big. Very big.

OK, I admit, I had an unfair advantage here.
No, it's not in Hungary.

it's not THE ONE but at least i'm on the right track

i don't know if the clue helped but thanks anyway

EDIT:

Thanks for the clue!

.

Lots of time spent on this one.  Know what it is, but inspected many of its locations, but unable to find the original.  Will take a break and look more later.  One of the ones I was able to locate, but not the correct one.