The Chimera was born from two monsters who were themselves children of the primordial earth. Her father was Typhon, the storm-giant with a hundred serpent heads who waged war against Zeus, the king of the gods, and was buried beneath Mount Etna as punishment. Her mother was Echidna, a creature with the face of a beautiful woman and the tail of a coiled serpent, who lived in a cave deep beneath the earth and gave birth to nearly every monster that would haunt the Greek world. From this pairing came the Chimera, a beast that combined the worst qualities of all three animals she resembled. She had the strength of a lion, the horns of a goat, and the venomous bite of a serpent. She breathed fire from her goat head, a flame so hot that it could melt stone.

The Chimera made her lair on Mount Cragus in Lycia, a region on the southern coast of what is now Turkey. From her mountain stronghold she descended upon the cities below, burning fields and devouring livestock. The king of Lycia, Iobates, had been sent a letter by Proetus, the king of neighboring Tiryns, who wanted a young man named Bellerophon killed. Proetus wrote that Bellerophon had tried to seduce his wife, and begged Iobates to dispose of him. Iobates saw an opportunity. He sent Bellerophon to face the Chimera, a task that no mortal had ever survived.

Bellerophon was not an ordinary hero. He was the son of Glaucus, a king of Corinth, and he possessed Pegasus, the winged horse born from the blood of the Gorgon Medusa, a creature so terrible that one look at her face turned living things to stone. Bellerophon had tamed Pegasus with the help of Athena, the goddess of wisdom and war, who gave him a golden bridle. Now he rode this divine steed into battle against the Chimera. The monster breathed fire that scorched the earth and roared with three voices at once, but Bellerophon stayed above her reach, wheeling in the sky on Pegasus's wings. From that height he rained down spears, and finally one found the soft flesh where the goat head met the lion body. The Chimera fell, her fire extinguished, her three heads silenced forever.

The death of the Chimera did not end her story. In the underworld, the realm of Hades, the god of the dead, she continued to exist as a spirit of terror. The poet Homer, writing in the eighth century BCE, placed her among the horrors that the dead must face, alongside the Gorgon and the Hydra and other monsters slain by heroes but never truly destroyed. Later artists would depict her in ever more elaborate forms, adding wings and extra heads. But the core of her legend remained the same: she was the monster that should not exist, the creature that proved nature could go wrong, and the beast that only a hero riding a divine steed could defeat.

The word "chimera" has outlasted the monster herself. In modern biology it means an organism made from two different sets of DNA. And in everyday speech it means any wild fantasy or impossible dream. All of these meanings trace back to a monster on a mountain in Lycia, a beast with three heads and one heart, who breathed fire and died under the spears of a hero on a winged horse. She was the first chimera, the original impossible thing, and her name still reminds us that the boundary between the natural and the unnatural is thinner than we like to believe.