It once took Mark Korb seven days to drain the pond in his Newcastle, California backyard. On Sunday, he woke up to find a sinkhole had accomplished the same feat in merely five hours.
"This looks like the moon," Korb told KCRA. Footage of the drained pond shows what indeed looks like a massive, gray crater.
Korb's discovery comes just two weeks after a 20-foot-wide sinkhole swallowed a man in Florida. A search for his body was called off on March 3, 2012, and he was presumed dead. The next day a second sinkhole formed less than two miles from the first, but no deaths occurred.
Last Tuesday, a sinkhole in Washington, D.C., closed down an entire block as officials worked to prevent a water pipe and nearby vehicles from caving in.
Just in Florida, thousands of sinkholes form each year, according to the Associated Press, but they're known to appear all over the U.S -- typically in areas where water has flowed underground and dissolved rock.