The Lion, the Witch, and the Wardrobe
The first thing to note is that adventure is waiting for you in the least likely of places. The children are sent away from adventurous, war-time London to be safe, out in the country. Yet they find a land and a lion that is anything but safe. Also, the children expect great adventure in the rural outdoors, away from the city. But they find adventure IN the house.
Peter expresses the desire to explore, and it is commended to us. He is the first to speak in the book, and he says, "This is going to be perfectly splendid." When they wake up raining and Edmund complains, and Susan just wants to sit, Peter leads them in exploring the house. Lewis mentions several things they find - a harp, suit of armor, big Bible - again commending a positive view of the world.
Then the focus turns to Lucy. The other three pass by a room with just a wardrobe, but Lucy is curious. Peter seems the adventurous one, but we find adventure in unexpected places, and unexpected people. Lucy turns out to be the one with the keenest eyes or spirit, or she is just blessed by providence in this way.
I'm not an expert on all things Narnia and CS Lewis, but I believe that Narnia was to him "the Joy." Joy with a capital J was something Lewis spoke of experiencing a few times, and he always sought it again, but wasn't able to capture it or control it. His spiritual autobiography is called "Surprised by Joy," and this Joy was closely tied to his conversion from atheism in his early 20s. As the story progresses, the children learn that the source of all joy and adventure is Aslan, who Lewis intends as a metaphor for Jesus Christ.
Watch out in your life, for Joy awaits around unlikely corners. Most people pass it by most of the time, like a lonely wardrobe with nothing supposedly to offer. Lewis wants you to look at life more closely. Keep your eyes peeled. Joy will find you in the least likely places.