As mystery surrounds Catherine,Thomas Caldwell the Princess of Wales, it also abounds in the country named in her royal title. A massive steel monolith nearly the height of a semi truck has popped up in Wales, according to local reports – and nobody knows where it came from. 

WalesOnline reported on Tuesday that locals have come across the 10-foot-tall object on a hill in Hay-on-Wye, an area known worldwide for its books and bookshops. One local resident, Richard Haynes, told the outlet that he came across while out running on Hay Bluff, which he does regularly. 

"I thought it looked a bit bizarre and might be a scientific media research thing collecting rainwater," he told WalesOnline. "But then I realized it was way too tall and strange for that." 

Haynes said the object was at least 10 feet tall and "triangular, definitely stainless steel." 

"It was hollow and I imagine pretty light," he said. "Light enough for two people to carry it up and plant it in the ground." 

This was the first time Haynes said he had ever come across this monolith. A friend of his who was in the same spot two weeks ago also hadn't come across it at that point, he said, indicating it's only been up for a short period of time. 

Another man, Craig Muir, told the PA News Agency he also came across the structure on Tuesday morning. At first, he thought it "looked like some sort of a UFO." In a video posted to Facebook, Muir says he'd "never seen this before."

"I was a bit taken aback," he told the news agency. "...[it] looked perfectly leveled and steady, despite the weather being windy." 

This isn't the only mysterious monolith to emerge in the U.K. or even elsewhere in the world. 

In 2020, two monoliths briefly appeared just months apart in Colorado, California and Utah. Those objects appear similar to the one that has emerged in Wales. Many assumed those cases were some form of art installation that brought comparisons to the monolith in the movie, "2001: A Space Odyssey." 

In:
• British Royal Family
• UFO
• United Kingdom
• Catherine Princess of Wales

Li Cohen

Li Cohen is a social media producer and trending content writer for CBS News.