Like the Drogorati Caves, the underground Lakes of Melissani will be a must for some holidaymakers, and a yawn to others.

You can take a boat ride over the supposedly bottomless depths, and marvel at the bizarre notion that it is fed (amongst perhaps numerous sources) by seawater which disappears into the ground at the Katavothres on the other side of Kefalonia.

This is, however, one of the attractions to visit at 'rush hour', when the sun shines directly on to the lake.