One summer day last July, a six-year-old boy was walking across a dune when he disappeared, falling into a deep, narrow hole in the sand. This and two other holes that have since appeared at Indiana's Mount Baldy are unlike anything scientists have seen before—it could be an entirely new geological phenomenon.


After being buried for three horrifying hours in the eleven-foot-deep hole, the boy was fortunately rescued. But the incident left an impression on geologist Erin Argyilan, who happened to be doing research at Mount Baldy that day and heard his parents' terrified screams. "I couldn't help in the moment," she told the Chicago Tribune, "So now I have to do what I can to learn why this is happening."


For the past year, Argyilan and other researchers have been poring over sediment samples, terrain maps, and wind patterns at Mount Baldy. The EPA has brought in ground-penetrating radar, which has identified underground anomalies but no straight answers. In the meantime, two other deep, narrow holes have suddenly appeared, and the dune in Indiana Dunes National Lakeshore is now closed to visitors. Researchers, however, will continue to closely scrutinize the ground for clues to the holes' origins.

The holes are geologically distinct from common sinkholes, which cave in after water eats away at underground rock. It's possible that they are appearing because of structures rotting underneath the sand. Mount Baldy has been slowly shifting south over the decades, burying trees and manmade structures in its sandy path. Perhaps the long buried past is rearing its head once again. [Chicago Tribune via LiveScience]