travels to spectacular habitats, including the Queensland rainforest, the Antarctic ice shelf, the Namibian dunes, tropical coral reefs and more. Discoveries and rarely heard recordings from the series include snow leopards singing love songs, the intimate chatter of ostrich chicks from inside their eggs, musical spiders, walrus's underwater courtship calls and more. But it's not just animals that make unusual noises. The series also captures the mesmerizing secret sounds of our planet, including the hum of deserts, drinking trees and the mysterious buzz of the northern lights.