Charybdis sat across from Scylla in a narrow strait, what is now the Strait of Messina, located between Sicily and Italy. This deadly whirlpool, the daughter of earth deity Gaia and the sea god Pontus took many lives with her swirling waters, according to The Hindu. The once-beautiful Charybdis offended Zeus, the king of the Greek gods, by stealing cattle from his son Hercules and allying herself with his brother Poseidon. He transformed her into the vicious whirlpool as punishment.

Odysseus also tangled with this monster. After the shipwreck of his vessel, his raft is caught in her waters. He manages to clamber onto a fig tree until his raft resurfaced from the monster’s grasp and he is able to row with his hands from the danger zone (via enotes). Jason and the Argonauts (pictured above) also successfully passed the two monsters on his quest for the Golden Fleece, according to Maritime Professional. 

Both Greek myths find their basis in reality; Charybdis, the whirlpool, and Scylla, a deadly rock or reef, offer a poetic explanation of the dangers of early travel in the western Mediterranean, according to Britannica. The phrase “between Scylla and Charybdis,” refers to the choice so many sailors of the ancient world faced where options boiled down to two unpleasant selections — what we’d call between a rock and a hard place now.