The colour of the water at Nafsika's cave and down the cliffs of the monastery in Palaiokastritsa is one of them.
Like the sound of the cicadas mixed to the sound of the waves, while lying on a pebbles beach in Kassiopi's bay.
Or the freshness of an unexpected cave, found following the footsteps of a bunch of Germans hiking up mount Pantokrator.
For other things, a couple of photo shots may help.
Sadly, tomorrow at this time I will be a caught by another kind of blue, in the livery of a Ryanair aircraft heading north.