Thra is a fictional planet in the universe of the 1982 film The Dark Crystal, created by Jim Henson and Frank Oz. It is depicted as a vibrant world filled with diverse ecosystems, including lush forests, mountains, and swamps. The planet is home to various species, including the noble Gelflings, the wise Skeksis, and the gentle Mystics. The central element of Thra is the Crystal of Truth, which maintains the balance of life on the planet. However, the Skeksis corrupt the crystal, leading to a decline in the planet's health. The story follows a young Gelfling named Jen on his quest to restore the crystal and save Thra.