TFZ is an exploration into various mysteries & peculiarities through the sands of time & space...
https://www.dailymail.co.uk/news/article-9029739/Silver-monoliths-appear-German-town-Spanish-hillside.html
Of course much larger versions would be tougher to remove.
https://www.theothersideofmidnight.com/topic/anomalies
https://desertshapes.blogspot.com/search?q=monolith