Final answer:
In 'The Magician's Nephew,' Polly is transported to the Wood between the Worlds when she touches a yellow ring, beginning her adventures with Digory.
Step-by-step explanation:
In The Magician's Nephew, when Polly touches the yellow ring, she is magically transported to the Wood between the Worlds, a tranquil forest filled with pools that lead to different universes. The yellow rings are used as a means of transportation in the novel, and touching one without wearing a green ring causes a character to vanish from their current world and emerge in the Wood between the Worlds. This event triggers the start of Polly's adventure with Digory in this prequel to the well-known Chronicles of Narnia series.