Thra is a lush planet located in a trinary solar system that made its debut appearance in the 1982 movie The Dark Crystal. It has a wide variety of ecosystems and creatures both sapient and non-sapient. It is also home to the eponymous Dark Crystal (also known as the Crystal of Truth). The dominant race of Thra is the urSkek race, although they are not native to Thra. Other races include the Gelflings, the Podlings and the Makraks.
Thra is located in an unnamed solar system that contains three suns and an unspecified number of planets. The three suns are named the Great Sun (the largest of the three), the Rose Sun (a smaller star with a pinkish hue) and the Dying Sun (the smallest of the three, and very dark comparatively). Thra must be fairly distant from the suns, judging from its teeming wildlife. Thra is orbited by a single dark moon. Many of the planet's inhabitants do not know of this moon's existence as it does not reflect light, unlike the moons of other planets.