The Polignano coastline features a large number of sea caves. Not to be missed are the Grotta delle Rondinelle and the more well-known Grotta Palazzese. The latter is carved out of the limestone by sea erosion and can be visited by boat. It can be accessed by land via a narrow stairway cut into the rock and by sea via two large natural openings. Inside are a vast semicircular chamber measuring some thirty metres in diameter and a smaller cavity with a pebble beach.