Are Haitians black, or at least of African origin?

I was randomly looking at pictures of people from Haiti and they look black to me, rather than some kind of native indigenous people of Mongoloid origin, like the Indians, Aztecs, Incas, Mayas, etc. But basically, did these people come from Africa? Or are they mixed with native Haitian descent? And if either, were they slaves? Because I had never heard that there was slavery in Haiti. I know there was all over the New World, but Haiti, I know nothing about. Anyway, please provide me with some links if you know of any. This could be a very interesting subject. Thank you and God bless.