Researchers are puzzling over a massive half-mile crack in the ground in a dry, desert region of Mexico's northwest.
The New York Daily News reported that the fissure -- which is up to 26 feet deep in some spots -- formed near Hermosillo in the state of Sonora.
According to The Weather Channel, the crack opened on Aug. 15 and split Mexico's Highway 36 so that drivers were forced to turn around and find detours.
Some scientists speculated that the crack was caused by seismic activity, while others said it was probably the result of an underground stream drying up, which created a void beneath the surface that then collapsed in on itself.
Martin Moreno Valencia, Chief Regional Station of the Institute of Geology at UNAM in Hermosillo told the Weather Channel that it is unlikely that an earthquake caused the rift to open because the two sides of the crack are level with each other. Generally, in earthquake damage, one side of a rift will jut up higher.
It has been a summer of mysterious holes opening in the Earth. U.K. newspaper the Mirror reported that a 100-foot sinkhole opened in northeast England's County Durham. The region has been experiencing heavy rain, so the hole -- which locals say is so deep that you "can't see the bottom" -- is continuing to expand outward, and may soon threaten local farmhouses.
That sinkhole is believed to be related to mining activities in the area.
In Siberia, researchers are studying that opened up in the ground earlier this summer. The holes are believed to have been caused by pockets of methane gas escaping from the ground as the region's permafrost melts after two summers that set high temperature records.
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