What are Hispanics? (not racist)?

This is what i don't get, central America, most of the Caribbean, and Latin America were all mostly colonized by Spain, (except for Brazil and french Guinea) quote me if I'm wrong. So Spain is a European country, so Spaniards are white if I'm correct, so how is it that most of the inhabitants of the Caribbean, central-Latin America area are not white? don't look white? or are considered white? they cant be Aztecs because Aztecs disappeared. My theory is that whites breaded with Aztecs before they disappeared, and there was so many of them that it created a new race, but u cant really create a new race can u? So my question is, what are the origins of Hispanics/ Latino's?