Regarding to Hazwan's request, I found something more interesting than Youtube music. Anyway, you could still go to youtube for more soothing music through this link: Nature Sound on Youtube
You could also visit The California Library of Natural Sounds (CLNS)'s lovely website, Listening to nature for an inspiring journey through California's nature.
I also discovered a cool website, which allows you to mix and match the nature sounds, e.g. bird song, rain , river, oceans, etc. You could also enjoy its beautiful slide show while you listen to its nature sounds.
Check it out:
