When opposed to reading, listening is a more natural approach to learning. Although written language only dates back to roughly 3200 BC, oral language has been around for a long time.

Now you can listen to the tremendous amount of general knowledge available on Wikipedia (audio article). You might even learn subconsciously if you listen to the audio while sleeping! Instead of earphones, you might use a bone conduction headphone or a conventional speaker if you want to listen a lot.