Melissani Cave

Melissani is what happens when a cave loses its roof over a lake: part of the ceiling collapsed in ancient earthquakes, opening an oculus that pours daylight onto water so clear the rowing boats appear to levitate on blue light. The lake is brackish and strange in its plumbing - dye tracing in the 1960s showed that seawater swallowed by the Katavothres sinkholes near Argostoli travels underground across the island to resurface here, a journey of two weeks beneath Kefalonia. The ancients felt the place's charge too: finds linked to the worship of the nymphs, including depictions of Pan, were recovered here, and the cave carries the name of the nymph Melissani. Visits are short and ceremonial - down the tunnel, into a boat, a slow circuit through the open bowl and the darker chamber while the boatman names the colours.

What you actually see

• The oculus - the collapsed roof framing sky above the lake.
• The blue hour - midday sun angling in and igniting the water.
• The dark chamber - the roofed half with its stalactites.
• The levitating boats - hulls floating on shadow in gin-clear water.

When to go

Come between late morning and early afternoon on a sunny day - roughly noon is when the shaft of light performs. On overcast days the magic dims considerably; June to September is the safest window.

Honest expectations

The boat circuit lasts perhaps 15 minutes, so the entry fee buys a short spectacle - and the best light hour is exactly when the queue peaks. Combine it with Antisamos beach and Drogarati cave to make the trip whole.

Nearby

Sami's harbour, Antisamos beach and the stalactite halls of Drogarati cave.