Door Of No Return

As I am an african history and culture passionate I would like to share with u a little bit of my knowledge of the Black Continent. What is the door of no return? It had started in XV ceintury and was persisting to XIX. It is located in Ghana. It was a place from where white people (clolnizers) took Africans for slavish work as they were their owns. Treated as things, not humans, were transported by ships in inhuman conditions to another countries. A travel was persisting something about 3 months or longer. During the travel a lot of people died because nobody care about the salves. It's a dramatic history point where is no information about how many Africans were died, it was just uncountable..If you want to see what I am talking about,check out the link below.
https://www.youtube.com/watch?v=UsO4aYNFc9U 
Bless up, Paula