There are many monuments worth visiting in Granada.
There is a list of the best ones with more information here
http://granadamap.com/places/monuments_to_visit_in_granada.htmIf you are going to do a lot of the monuments it may be a good idea to buy the "bono turistico"
which a ticket which gives you access to several places at reduced cost.
More info here.
http://granadamap.com/bono/