XML : Pull data between

I have a very large XML file that I need to do some data analysis on.

I cant open the file in any XML parser or Excel as it is too large. I would like to grab every value that is inside and then write them to a file.

Can I do this by using terminal in Mac OSX? I have access to a Windows machine with Cygwin too.

Ideally my end goal is to have a file that shows every unique entry in this node and then give me the count.

Ex: London 500 New York 600 Seattle 500

  <product id="">  <city>      <id>abilene</id>      <name>City Name</name>      <lat>32.445587</lat>      <lng>-99.755331</lng>    </city>  </product>    

Thanks,