The Whispering Woods is a deep forest that protects the Crystal Castle, the base of operation for She-Ra, as well as shielding the kingdom of Bright Moon, the largest kingdom of Etheria.
It was the main setting of "The Sword: Part 1", the first episode of She-Ra and the Princesses of Power. It also is the place of Madame Razz's home, as well as of other wild creatures such as the Etherian Deer, giant mammals and bug-like monsters.
In "The Battle of Bright Moon", it was frozen after Entrapta's plan to hack the planet of Etheria. It regrew, with help from the Princesses after the Horde retreated.
In Season Two we learn that Bow grew up at The Library in the Whispering Woods with his parents and 12 older siblings.
In Season Three, the heroes battle bots and capture a bot for Bow to study.
In Season Four, Lonnie, Kyle and Rogelio had a break-down in the Woods in their transport and were nearly destroyed by an Acid rain, but Kyle repaired the damage, saving them all.