Grotta della Poesia, Roca Vecchia

The roof of a coastal cave gave way here at some point in the last few thousand years and left an almost perfectly round basin, ten metres or so across, connected to the open sea by a short tunnel through the rock. The water inside is the same colour as the water outside but flat, and the walls around it are pale, layered limestone.

It is a shape you cannot invent: seen from the rim, a circle of blue inside a plain of grey stone, with the Adriatic a few metres beyond. Wide frames from the north side get the pool, the tunnel mouth and the sea in one image; closer in, the layered rock makes a good clean background at eye level.

The surrounding site is a Bronze Age and Messapian settlement, still being excavated, and it is open ground with no shade at all. That makes early morning the only comfortable slot in summer as well as the only quiet one — from mid-morning in July and August the rim is lined with swimmers.

Access arrangements and any swimming restrictions have changed more than once in recent years, so check what applies before building a session around the pool itself; the rock platforms around it are photogenic in their own right.