The Green Belt was an unexplained area of vegetation along the coast of Voya Nui. It was located further inland from the ring of ice which surrounded Voya Nui's U-shaped coastline. The origin of the green belt was a mystery to the Matoran.
A hidden entrance in the Green Belt opened up to a staircase with 777 stairs which descended to the Chamber of Life where the Mask of Life was hidden.
The Green Belt contained the only passageway to the Mask of Life.
The Green Belt was a strange forest which encircled the island of Voya Nui. Its origin was unknown. Some of the Piraka believed that the Mask of Life could be found here and that its power had made the plants grow. The secret entrance to the Chamber of Life could be found here.
- Greg Farshtey imagined the Green Belt as similar to a northeastern US forest to differentiate it from the vegetation on Mata Nui.