Answer:
A simile is a figure of speech involving the comparison of one thing with another thing of a different kind, used to make a description more emphatic or vivid (e.g., as brave as a lion, crazy like a fox ).
Step-by-step explanation:
THE GOLD RUSH SWEPT ACROSS AMERICA LIKE WILDFIRE WHEN GOLD WAS FOUND IN 1848.
The simile in this sentence is "GOLD RUSH" and "WILDFIRE". The Gold Rush swept the country like a wildfire.
Another example would be "Your explanation is as clear as mud."
The simile in this sentence is "explanation" and "mud". How clear is mud? Not at all. So it is saying a person's explanation is not clear at all, clear as mud.
Hope this helps :)