“Marines are investigating 3 ancient pyramids discovered in Antarctica.”

An old conspiracy theory about pyramids in Antarctica has new legs. 

According to a blog post being shared on Facebook, “Marines are investigating 3 ancient pyramids discovered in Antarctica.” 

The post appears on a site titled, “Weird but true.” 

In fact, it’s not. 

This post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

The U.S. Marine Corps did not immediately respond to PolitiFact’s questions about the blog post. But claims about these supposed pyramids have been around since at least 2016, according to Snopes, which looked into the alleged discovery a year later.  

In reality, there’s just one, and it’s a mountain.

“This is just a mountain that looks like a pyramid,” Eric Rignot, a professor of Earth system science at the University of California, Irvine, and a senior research scientist at NASA, told LiveScience in 2016. “Pyramid shapes are not impossible — many peaks partially look like pyramids, but they only have one to two faces like that, rarely four.”  

The mountain doesn’t have a formal name, but it’s one of many peaks in the continent’s Ellsworth Mountains. 

Mauri Pelto, an environmental science professor at Nichols College, told LiveScience that freeze-thaw erosion likely caused the pyramid-like shape of this mountain and others, such as the Matterhorn in the Alps.

We rate this post False.