Unzip this file to your scenario subfolder in your Age of Mythology folder. This background replaces the "lighthouse" background in the main menu. Since the main menu alternates between bacgrounds, you will still see the "Norse snow scene" some of the time.
To get rid of this file, simply delete, and the "lighthouse" will be restored.
Scene desription: Waterfalls along a seashore :-p... Weird combination but looks good :)