In Attiki there are three rivers: the Kifissos, the Ilissos, and the Iridanos. From these, and from the  700 streams that used to exist,  only Kifissos has managed to remain on the surface. The rest have been covered to facilitate urban development, and flow through underground canals beneath the streets of modern Athens. Part of the course of Iridanos, connecting Lycabettus Hill-Syntagma Square-Mitropoleos and Ermou streets,  is exposed  at the archaeological site of Kerameikos, and also within the underground Metro station at Monastiraki.
Under thick shade on the banks of the Ilissos, Socrates once sat to talk to Phaedrus about love and soul (Plato’s Phaedrus). In 1948, for still unknown reasons, work began covering  the river bed, and so the Ilissos rolls on underneath  Agios  Konstantinos Avenue. However, at the Faliro Delta where it drains, it creates a wetland in which many species of birds and wildlife find shelter.
The only river that has remained on the surface, with the attendant cost of pollution however, is the Kifissos. Sources of the Kifissos include Tatoi, Varibobi, and Kefalari. (Water from there is used before reaching the river).  There are also some streams that feed into the river, like the Podonyftis ,emanating from Mount Penteli. The Kifissos has water throughout the year, but really no part of it is attractive to visitors.