Nina investigates how caves were formed, with the help of Belle her hearing neuron.

Originally released by BBC, 2013. Streaming video file encoded with permission for digital streaming by Infobase on November 17, 2016.

Meet the Neurons (0:56); --How Are Caves Made? (2:10); -- Senses Experiment (3:25); -- Can Water Dissolve Rocks? (3:13); -- Cave Formation Experiment (2:00); -- Summary: How Are Caves Made? (0:41); -- Credits: Caves—Nina & the Neurons: Earth Explorers (1:32); .