Authentic paella?

Hi everyone! I know we have some Spanish members here (Jiza, Loretta...anyone else?) Anyway - I was recently asked for an 'authentic' paella recipe, and realized I don't have a clue! I'm wondering what to you is an 'authentic' paella? Do you need a paella pan? What kind of rice? What should go in it? What are the must-have characteristics? Please chime in whether you're Spanish or not, if you love paella :)
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