Magic ring

Appearing as a main plot device in The Magician's Nephew, these yellow and green rings were used to transport people to and from the Wood between the Worlds from various worlds.

Background Information
The rings were created by Andrew Ketterley from a magical power he discovered in a box left to him by his part-fairy godmother Mrs. Lefay. The box originally came from Atlantis and the dust was discovered by Uncle Andrew to have been brought from another world as our world was just beginning. It is possible that the dust may have come from the Wood between the Worlds itself. Presumably it had been used by the Atlanteans for travel to different worlds, explaining some anomalies such as Jadis, who is described both to be descended from Adam's first wife Lilith, and is at the same time native to Charn.

Function
To work, the user must have skin contact with the rings, or with a person in contact with the rings. Upon touching a yellow ring, the user will be taken to the Wood between the Worlds, emerging from the pool corresponding to the world the user was present in at the time. From here, the user is able to enter any other world by touching a green ring and jumping into the pool corresponding to the world of choice. Only inhabited worlds may be entered - Charn's pool dryed up when it's last living inhabitant left it.

The Magician's Nephew
After he had created them, Uncle Andrew spent a while experimenting by tying the yellow rings to guinea pigs. This resulted, to the delight of Uncle Andrew, in several guinea pigs disappearing entirely to 'another world', though of course they had no means of getting back, or telling him about it. Therefore, in order to test for sure whether it would be safe for human travel, he tricked Polly Plummer into touching one of the yellow rings. Shortly afterwards Digory does the same in order to rescue Polly, bringing with him two green rings. Digory finds himself transported to the Wood between the Worlds where he finds Polly and the various guinea pigs. Before returning, the two use the green rings to enter and explore the dying world of Charn, where Digory awakens Jadis, last empress of Charn. Upon leaving with the yellow rings, and returning to their own world with the green rings, they inadvertantly bring Jadis back with them. Jadis immediatly goes to wreck havok throughout London, with Uncle Andrew at her tail, and in the effort to return her to her own world, Digory, Polly, Jadis, Uncle Andrew, The Cabby and his horse Strawberry end up in Narnia to witness it's creation. At the end of their adventure, Digory is commanded by Aslan to bury the rings so that no one can use them again.Digory buried the rings in his back garden.

The Last Battle
The Seven Friends of Narnia gathered together and conspired to retrieve the rings. After Eustace and Jill were summoned back to Narnia, Peter and Edmund sneaked into the garden of Professor Kirke's old house and dug up the box containing the rings. However before they could use the rings, the remainder of the Seven friends present were summonned to Aslan's Country when the train they were travelling on crashed.