Inside the caves of Mount Baigong, and in the surrounding area, there are dozens of strange pipe-like structures, subject to all sorts of conspiracy theories and rumors.
Known as Baigong Pipes, the first references to the structures appear to be from the Chinese state media affiliated news site Xinhua News Agency. According to the article, the pipes were made up of "30 percent ferric oxide [iron oxide] with a large amount of silicon dioxide and calcium oxide", while 8 percent of the makeup of the pipes could not be identified by the scientists studying it.
The intrigue of 8 percent material being unidentified, large amounts of iron oxide deposits, and the fact that they do sort of look a lot like pipes, has led to wild speculation from conspiracy theorists. According to various YouTube videos, and articles from websites that also do a lot of Sasquatch content, the pipes are evidence of advanced but ancient civilizations or, equally ancient aliens.
So what actually are the Baigong pipes? Well, they do appear to be ancient, as conspiracy theorists would have you believe. But that's because they were likely formed by geological processes.
Structures similar in look and/or composition to the Baigong pipes have been found in south Louisiana, and elsewhere.
The "pipes" found in south Louisiana, like the Baigong pipes, are most likely fossilized trees according to the geologists who studied them.
"The cylinders are inferred to be tap-root casts of fossil trees in which sediments replaced wood and pedologic and diagenetic processes caused the external form of the tree root to be preserved while the internal structure was lost," one team explained in a 1993 study. "The characteristics of cylinders developed in the different stratigraphic materials were contrasted to assess the influence of time and lithology in their development and preservation."
Minerals formed around the roots, before those roots rotted away inside, leaving the hollow pipe effect. This explanation has also been given for the Baigong pipes, according to Atlas Obscura, with experiments confirming that the "pipes" themselves contain organic plant matter.
Another explanation suggests that the pipes were made in a sort of natural cast. According to that theory, fissures were left in sandstone by the Tibetan Plateau uplift, which were then filled with iron-rich sediment during flooding of the area.
Either way, neither process requires aliens, or pipes to take away their alien waste.