Melissani Cave ( Kefalonia ) is an underground lake that you have to take a boat through. It is shaped like the letter B, with two chambers. The roof the first part of the cave that you encounter caved in years ago, allowing sunlight to stream into the cave. At noon when the sun is directly over the cave, the sunlight makes the turquoise blue water glow, reflecting the color all over the interior of the cave. Excavations in 1951 and 1962 unearthed many artifacts dating to the 3rd and 4th century B.C. To see the cave, you and about 10 other people board a small boat that has a guide to row you through the chambers. While the first chamber is full of sunlight, the second chamber is dark and filled with algae covered stalactites. The water is a mixture of salt and fresh water, replenished by a spring deep under the lake. No trip to Kefalonia is complete without seeing Melissani Caves. It is very near Drogarati Caves, so a trip to both in one day is perfect.