Is romeo and Juliet is real story? i searched on net n most say its made up but if its not real thn castle?

ppl say tht romeo and juliet story is not a real story thn how come thr is castle of juliet and tht balcony (Casa Di Giulietta) and place whr romeo lived(Casa di Romeo a few steps away from Piazza dei Signori)????????????????? thr also tombs of both of them in Italy???????? so is this real or made up??????????????????