Valhalla is one of the hundreds of moons orbiting the enourmous gas giant called Thor. It is about half as large as Earth, but the gravity is only slightly less than Earth's.
The entire moon in covered in a vast dense jungle, even more dense than planet Glorph's planetwide jungle. Valhalla is home to several deadly creatures, and many of the plants are carnivorous. One of the only reasons this incredibly harsh world is colonized other than for research is the variety of valuable plants that grow here. Many are used for medicines, and one carnivorous plant even grows a valuable gem in the center of it's flower. (See Valhallan Gem Plant)
The small outposts and villages on Valhalla's surface are almost constantly subject to attack from the moon's ravenous beasts, and one of the only safe places on the planet's surface are a few GDA bases set up to protect the colonists (although not enough GDA troops are available to be effective in protecting the colonists), and the moon's capital spaceport city.
Valhalla's wildlife is so dangerous that citizens of the world are permitted to own high output energy weapons to dedend themselves, because some of the beasts are so powerful that it would take several power cells to kill even one of them.
Valhalla is also used for the final training stage of the GDA's elite Jungle Troops.