The “monolith” in Utah is a fake. A closeup shows pop rivets holding the skin onto I assume a metal or wood inner frame. Also, it looked like very thin metal based on the ripples. One of the other “monoliths” I saw on the news showed a close up and I could easily see very crappy, cold welds joining smaller sheets together. Welds we call “bird poop”. I do a lot of metal fabrication and the two I saw were poorly made fakes. Intended to be “art” I guess.