Sinkholes form as limestone gradually dissolves and collapses. See some of the most recent and largest sinkholes reported.
In Bayou Corne, La., a sinkhole has been widening since 2012, reaching some 25 acres, the New York Times reported. The Times describes the discovery of the sinkhole: "in the predawn blackness of Aug. 3, 2012, the earth opened up — a voracious maw 325 feet across and hundreds of feet deep, swallowing 100-foot trees, guzzling water from adjacent swamps and belching methane from a thousand feet or more beneath the surface."
Now, more than a year after it appeared, the sinkhole is about 25 acres and still growing. It even has its "own Facebook page and its own groupies, conspiracy theorists who insist the pit is somehow linked to the Gulf of Mexico 50 miles south and the earthquake-prone New Madrid fault 450 miles north," the Times reports.
In this photo: A truck hauling dirt rides along a berm set up to contain the sinkhole.
See related graphic: How limestone sinkholes form
Watch related video: Montreal sinkhole swallows backhoe