What causes sinkholes

Published On: Aug 12 2013 12:48:02 PM CDT   Updated On: Mar 26 2015 02:46:05 PM CDT
brazil sinkhole bus

In March 2015, a sinkhole swallowed a tour bus in northern Brazil. The incident happened near a flooded river. Everyone aboard escaped safely. Take a look at what causes a sinkhole and some other notable sinkholes that have made headlines.