The Eagle by Alfred Lord Tennyson

He clasps the crag with crooked hands;
Close to the sun in lonely lands,
Ring'd with the azure world, he stands.

The wrinkled sea beneath him crawls;
He watches from his mountain walls,
And like a thunderbolt he falls.

Which type of figurative language is used in the bold line?

Metaphor
Onomatopoeia
Personification
Simile