This is the 749th most frequent German word.
überall
Everywhere.
In this sentence, 'überall' means 'everywhere' and is used as an adverb describing the location of the books.
Überall im Haus liegen Bücher herum.
Books are lying around everywhere in the house.
Here, 'überall' indicates searching in all possible places, emphasizing the breadth of the search area.
Ich kann den Schlüssel überall suchen, aber ich finde ihn nicht.
I can search for the key everywhere, but I can't find it.
In this usage, 'überall' refers to a global scale, expressing that the diversity of cultures spans the entire globe.