A mother is in custody after her two young children were found barefoot, dirty and living in a wooden shipping crate in an underground cave — part of a massive subterranean network carved out beneath Kansas City.

A look at the history of the caves:

WHY ARE THE CAVES THERE?

Extensive limestone mining in the late 1800s and early 1900s created the millions of square feet of caves that are scattered throughout metropolitan Kansas City, in Kansas and Missouri.

Syed E. Hasan, a geosciences professor emeritus at the University of Missouri-Kansas City, said the “very pure” limestone was ideal for cement production to shore up the city’s rapid expansion at that time. Farmers also used it to improve soil. Read more.