Which sentence uses a simile?

 - The running children are a stampede of horses.
 - The children ran by like a stampede of horses.
This sentence uses a simile:
The children ran by like a stampede of horses.
The words children and stampede are compared using the word like.
This sentence uses a metaphor:
The running children are a stampede of horses.
The words children and stampede are compared without the word like or as.