Eridanus

Eridanus corresponds with current Po River, the main river of Italy; it is associated with two Greek myths, both likely to be derived from the shape of the constellation — that of a very twisty path. Eridanus was sometimes considered to be a river which flowed from the waters of Aquarius, and in such situations, Aquarius was considered to face Eridanus (requiring a change of angle, and this required the redesigning of how the stars of Aquarius connect, so that the water poured onto the same side as Eridanus).
Eridanus was more usually connected to the myth of Phaëton, who took over the reins of Helios' (i.e. the Sun's) sky chariot, but didn't have the strength to control it, and so veered wildly in different directions. The result was that sometimes the chariot got too close to earth, creating desert and burning people's skin (a myth Greeks considered to explain the skin of the Ethiopians). Zeus intervened by striking Phaëton dead with a thunderbolt. The constellation was considered to be the path Phaëton drove along, according to the mythology. In later times, it was considered to be the river of the underworld that he fell into.