The myth stated that Phaeton bragged to his friends that his father was the sun-god. His friends refused to believe him and so Phaeton went to his father Helios, who swore by the river Styx to give him anything he should ask for in order to prove he's in fact his father. Phaeton wanted to drive his chariot (the sun) for a day. Though Helios tried to talk him out of it, Phaeton was adamant. When the day came, Phaeton panicked and lost control of the mean horses that drew the chariot. First it veered too high, so that the earth grew chill. Then it dipped too close, and the vegetation dried and burned. He accidentally turned most of Africa into desert; burning the skin of the Ethiopians black. Eventually, Zeus was forced to intervene by striking the runaway chariot with a lightning bolt to stop it, and Phaėthon plunged into the river Eridanos. His sisters the Heliades grieved so much they were turned into poplar trees that weep golden amber.

Source: WikipediA -> http://en.wikipedia.org/wiki/Phaeton