The Corrupted Temple
The Corrupted Temple is a zone in the Rain of Fear expansion. It is an instanced raid zone version of the north wing of Temple of Veeshan.
This zone is linked to Western Wastes.
To enter the zone and begin a raid, head to Western Wastes (Velious). At the entrance to Temple of Veeshan there is a purple crystal. Clicking the crystal will spawn "a temple custodian". If you have between 6 and 54 people in your group/raid, you will be assigned the raid instance upon telling the NPC "enter". Once you have the expedition, say "ready" to enter.