Lake Stymphalia is associated with many legends. It is located between the mountain of Kyllini and Mount Oligyrtos. Its depth is about 10 meters, it has fresh water and it covers an area of over 7,700 acres in winter and 3,500 acres in summer. It took its name from Stymphalos, the son of King Arkadas. According to mythology, this is the lake where Hercules accomplished his 6th feat by exterminating the Stymphalian hens that lived there and created problems in the region. In the lake there are natural sinkholes that send the water into tunnels for the water supply of the plain. Stymphalia is one of the few wetlands of the Peloponnese as it is a shelter for 133 species of protected, endangered and migratory birds. Furthermore, this is the natural habitat of  Phixinellusstymfalicius, a species of endemic fish which survives even in the periods of drought as it immerses in the mud. Here you will also see wild ducks, eagles, kingfishers, partridges, owls, herons and many other species of birds that live and breed there.