Acheloos is the second largest river of Greece, with a length of 220 kilometers, and the first with respects to the total amount of water. It even forms a natural border between Epirus and Thessaly regions.

The construction of hydroelectric dams alongside Acheloos was an effort to control its waters, since the river was famous for its floods ever since the time of the Labours of Hercules. Actually, Ancient Greeks worshipped Acheloos as a god, because of the fear they felt for it.

The most beautiful part of Acheloos is its valley, which besides its natural beauty, also has a cultural and religious heritage lost in the mists of time. Acheloos valley was the cradle of ancient civilisations because of its convenient geostrategic position, as well as the wealth that the river lavishly provided.