This spell functions like
hallucinatory terrain, except that it enables you to make any
area appear to be something other than it is. The illusion includes audible, visual, tactile, and olfactory elements. Unlike
hallucinatory terrain, the spell can alter the appearance of structures (or add them where none are present). Still, it can't
disguise, conceal, or add creatures (though creatures within the
area might
hide themselves within the illusion just as they can
hide themselves within a real location).