reporter: elmina castle. a place of terror for west africans.urning to where the trauma of slavery began is a way of marking a new beginning for many african americans. >> this is the door of no return. now, the door of return. reporter: coming here helps them connect with their heritage. marcus can't imagine ever going back to the u.u.s. marcus: nothing has changed. and for me, i just feel that, for us, we have to make our own change. we cannot allow, or basically expect somebody elsese to makea change when they have been the same way for years. the french have a saying -- things change, but things stay the same. so for me, i can't live in that existence. reporter: by crossing the ocean to come to africa, afia khalia and marcus taylor are making their own change. host: the largest coal-producing region in e u.s. stretches from pennsylvania in the north to alabama in the south. the heyday of the mining industry is long past, though. between 2008 and 2017, around half of all coal mines in the country shut down, and over a third of the jobs in the