<http://schema.org/mainEntityOfPage>
<http://www.popularmechanics.com/adventure/outdoors/tips/a9192/why-sinkholes-appear-and-how-to-fix-them-15704756/True>
<http://www.popularmechanics.com/adventure/outdoors/tips/a9192/why-sinkholes-appear-and-how-to-fix-them-15704756/>