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.

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.

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

Stuart and Tonya Junker loved their quiet neighborhood near South Dakota's Black Hills — until the earth began collapsing around them, leaving them wondering if their home could tumble into a gaping

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.