C.S. Lewis's series, The Chronicles of Narnia, explores the lives of the Pevensie children as they discover a magical land that can be reached through the back of a wardrobe at Professor Digory Kirke's home. The land they discover is called Narnia, and it's full of people, animals, and flora they've never experienced in quite that way before.
Aslan, an anthropomorphic lion, leads the persecuted inhabitants of Narnia, and legend says he created the world in the first place. Geographically, Narnia is mostly forested, with some marsh in the north. The northern border is the River Shribble, the Eastern Ocean flanks the east, Archenland borders on the south, and a series of mountains line the western border. The Great River of Narnia flows through most of the country and creating a natural gathering place for communities along its banks.
Narnia is home to dwarfs, fauns, satyrs, tree people, a variety of animals, witches, giants, centaurs, and dozens of other mythological creatures call Narnia home. Humans are able to enter Narnia in various ways throughout the books including Professor Kirke's wardrobe, Susan's horn, Uncle Andrew's magic rings, Eustace's attic picture, and the Experiment House door.
Narnia has some quirks that separate it from the Earth-like world that it often resembles. The sky in Narnia is a dome, and in The Voyage of the Dawn Treader the place where the sea and sky meet is explored. Stars are alive and can move at will. The sun revolves around the world and some flora and fauna inhabit it. Time on Narnia moves more quickly than on Earth, but not at a constant rate. When the Pevensies return to Narnia in Prince Caspian: The Return to Narnia, 1,300 years have passed in Narnia while on Earth the children are barely older than they were when they left.