Where in the world is Serbia?

Ok, you didn't have to add the "in the world" thing, it's disrespectful. And it's basic geography.
Located at the crossroads between Central and Southern Europe Serbia is found in the Balkan peninsula and the Pannonian Plain. Including Kosovo, it lies between latitudes 41° and 47° N, and longitudes 18° and 23° E

You also could have looked it up on the map.