The island Crete once housed a terrifying monster that fed on people. That's why Daedalus the engineer was commissioned to build a maze in which the monster could be locked up.
Daedalus constructed a labyrinth with so many twisting tunnels that any mortal who entered it would never found his way out again.

All the same, the beast in this labyrinth still had to be fed with human flesh, year in, year out. That is, until the day Theseus, royal prince of Athens, decided to kill the monster. This was a great shock to his beloved Ariadne. She therefore had the same technical genius Daedalus make a ball of thread. It was as long as the tunnels of the labyrinth.

The end of this thread was tied at the entrance to the maze. While he wandered about in the labyrinth, Theseus unraveled the ball a little more at very turn.
He slew the monster after a fierce fight. And then he was the first mortal to find his way safely out of a labyrinth with thousands of dead-end tunnels and apparent exits: he was led by the thread of Ariadne.