If you are counting stone circles, it seems unfair not to count 5000 year old mounds in the US.
I will resist the temptation to joke about time travelling aliens
0 - Why do the tourists have so many Disney shirts, hats, and backpacks???
1 - https://www.tuatha.ie/drombeg-stone-circle/
2 - https://www.english-heritage.org.uk/visit/places/stonehenge/...