Why did Odysseus smear wax in his men's ears?

Odysseus smeared wax in his men's ears to protect them from the enchanting song of the Sirens. The Sirens lured sailors to their doom with their beautiful voices, causing them to steer their ships toward dangerous rocks. By blocking his men's hearing, Odysseus ensured they would not be tempted, allowing them to safely pass the Sirens while he, curious to hear their song, had himself tied to the mast of the ship.