About 150 neighbors from the Hideaway Hills subdivision sued the state for $45 million to cover the value of their homes and legal costs after giant sinkholes opened.

Families in a South Dakota neighborhood are fearing for their safety as sinkholes have appeared around their homes in the area above an old underground mine.

Sinkholes are fairly common, due to collapsed caves, old mines or dissolving material, but the circumstances in South Dakota stand out, said Paul Santi, a professor of geological engineering at the Colorado School of Mines. The combination of such large sinkholes endangering so many homes makes the Hideaway Hills situation one to remember.