The Circle of Gaea

The Circle of Gaea is an enchanted circle created for the Elementals to perform the Ritual of the Guardians in order to stop the weather from wreaking havoc all around the world every hundred years. The demon Tempest could control the Elementals' powers while standing inside the Circle.

History
Every hundred years, the Circle of Gaea appears in a different location. In 2002, it was located in Golden Gate Park. The Charmed Ones, Leo Wyatt, Darryl Morris and the Elementals, Tyler Michaels, Rafe, Gabrielle Chambers, and Muriel Hammond found their way to the Circle where they confronted the demon Tempest. With much effort, they defeat the demon and successfully perform the ritual to save the world.