https://www.cnet.com/news/mysterious-monoliths-in-utah-romania-and-california-everything-we-know-so-far/
On the same day the Utah monolith disappeared, another one appeared in Romania. When the Romanian monolith disappeared four days later, another appeared in California! So far one of the leading theories is they are the work of artist John McCracken. Who died in 2011. *do do do do do do do*