Take a trip to nearby Conca dei Marini to visit the stalactites of the Grotta di Smeraldo or Emerald Grotto , where the waters are as brilliantly emerald green as those of Capri 's Grotta Azzurra are blue , believed by many to be even more beautiful .
Capri 's Grotta Azzurra 's waters are blue , but they are not as pretty as The Emerald Grotto 's .