A sinkhole is a depression that forms in the ground caused by erosion underneath. They can vary from a few feet to hundreds of acres and from less than a foot deep to deep wells in the ground, according to the U.S. Geological Survey.

Here are some significant sinkholes that have formed over the years:

1. A large sinkhole destroyed two homes and swallowed a boat in June in Land O'Lakes, Florida. A third home lost about 45 feet of driveway and a septic tank. A total of 11 homes were affected by the sinkhole, the largest in three decades in Pasco County.

2. A sinkhole 40 feet wide and 25 to 30 feet deep opened below the National Corvette Museum in Bowling Green, Ky., on Feb. 12 2014. It swallowed eight rare and one-of-a-kind Corvettes that had an estimated value of $1 million.

3. A mammoth 320 feet across and 75 feet deep sinkhole swallowed five Porsches from a German car shop in Winter Park, Fla., on May 11, 1981.

4. A sinkhole 17 feet wide and 20 feet deep opened on Faithway Drive in Seffner, Fla. on Aug. 19, 2015. It was the same location that a sinkhole opened in March 2013, destroying a house and killing a man who lived there.

5. A 60-foot-wide sinkhole damaged buildings at the Summer Bay Resort in Clermont, Fla., on Aug. 12, 2013.

6. A driver was rescued from a sinkhole caused by broken water line in Toledo, Ohio, on July 3, 2013.

7. A Cadillac Escalade fell into a sinkhole at a Milwaukee intersection on July 23, 2010 after a sewer main collapsed.

8. A Los Angeles fire truck fell into an abyss in the Valley Village neighborhood on Sept. 8, 2009. The hole opened near a broken water main.

9. A water pipe broke and caused a major sinkhole next to I-25 near 58th Avenue on Feb. 8, 2008, in Denver, Colo.

10. A sport utility vehicle got stuck in a sinkhole in the Brooklyn area of New York after a water main break caused the street to give way on March 27, 2006.

Tim Harlow