There is a common misconception about the ending of C.S. Lewis's The Lion, the Witch and the Wardrobe. The four Pevensie children—Peter, Susan, Edmund, and Lucy—do not return to 1940s England by simply walking back through the wardrobe.
After ruling Narnia for ~15 years (Narnian time) as Kings and Queens, they chase the White Stag into a thicket in the Western Woods. There, they encounter the lantern-post—the same marker near where Lucy first entered. Pushing through the thicket, they tumble out of the wardrobe into the spare room at Professor Kirke's house.
The wardrobe remains the singular threshold between the two worlds in this book. (Later books introduce other portals: a painting, a door in the air, magic rings.)