"The world over" is a kind of idiomatic expression using a poetic inversion of the typical word order. Here "over" does not mean "above" but rather "covering", as in "You should put sunscreen all over (your body) before going outside"
The (whole) world over (phrase): everywhere in the world, from all over the world.
Although written in English, Rawling's books about her beloved boy wizard are known the world over.
Although not originally native to many cultures, some form of bread is eaten the world over.
See also the similar idiom "around the world":
The Louvre in Paris attracts tourists from around the world.
Her books are famous around the world.
You can use a similar inversion with other nouns and prepositions, again as a kind of poetic device:
The dinner outside was particularly nice as there was a full moon.
Some philosophers speak of "the garden within" as a metaphorical place that needs regular care to avoid being overgrown with weeds.