In 1868, while searching for ore-bearing stone in Iowa, miner James Rice came across an especially striking sight. An underground cavern filled with striking cave formations made up of crystals including argonite, travertine, satin stalagmite, stalactite, and calcareous spar. Below the cavern roof sits a small pool of crystal-clear water.

The underground wonder was known as Rice’s Cave at first, then Linden’s Cave when the property was transferred to Charles Linden. It became known as Crystal Lake in the 1930s, when Bernard Markus (Linden’s son-in-law) took over operations. Today, it is one of the longest-operating show caves in the state of Iowa.