The sink holes of Argostoli are still considered a mystery and are part of a rare geological phenomenon of Kefalonia. Katavothres is located 3km outside Argostoli and it is a must-see attraction because of its natural beauty and a famous club-café situated there.
In 1835, the phenomenon was rare enough that the English built some corn mills and while earthquakes broke the water wheel, amazingly nothing happened to alter this trend of water coming in and going under. One could well ask where the wheel was set up so as to work. They needed flowing water. This is where the rare geological formations came in to play.
At Katavothres the sea flows inland and enters sinkholes on the earth that is below sea level. It is assumed that there are caverns below the seabed which is where the water flows in. The mills used to be run in these holes. The water would flow swiftly through the artificial channels and the wheel would start spinning.
In 1963, Austrian geomorphologists added some purple dye to the water and followed its course only to make some surprising discoveries. The water flowed in underground rivers, then mixed with rainwater and finally reached the Melissani Lake almost fifteen kilometers away in a semi-salted form. From there, the water flowed in to the sea at the village of Karavomilos. The purple water travelled two weeks to make this trip across the island.
The phenomenon is still a mystery. There are a lot of theories that have been circulated but none can be unquestionably substantiated. A good idea is to go to Katavothres, enjoy the amazing sites and leave the questions as those known only to nature.