What events took palce before California joined the United States?
List at least three.

California was created as a state out of the unorganized territory of
the Mexican Cession in 1850.

So, the Gold Rush of '49 for one.

If this is a school assignment, and if you can find Google Answers,
then you can find at least one website that will answer your question.

If this is not a school assignment, all the above still applies and
you can save the price of your question.

you can check this site
http://memory.loc.gov/ammem/cbhtml/cbmexico.html or many other site in
google .it tells about the history of california before it joined
united states you can pick out events from it if you want ;)