During the warEdit
Stable 101 was the last stable Stable-Tec officially finished. The stable was given excessive medical and cybernetic technologies as part of its own social experiment. The Stable was built in Everfree Forest on the site of the castle where the Elements of Harmony were originally kept.
After the WarEdit
This particular stable housed Earth ponies exclusively. The stable survived for over a century before a young stallion began to question the Stable's way of life. This young stallion eventually decided to poison the stable when the inhabitants refused to open the stable door and killed the majority of the ponies inside. Only a few of the stable dwellers survived. Red Eye used the technology and resources of his home stable to begin trying to fix the wasteland.
Red Eye built his cathedral over the ruins of the castle and Stable 101. The Cathedral was where Red Eye planned to ascend into godhood and begin a new unity, filling the void left by The Goddess. Stable 101 and the Cathedral were both destroyed by Littlepip, when she rigged Autumn Leaf's Star Blaster to explode.