A disused building is seen on the beach where thousands of slaves were shipped away from the historic slave port of Ouidah, Benin, July 17, 2019. The 400-year anniversary of the first slave boat to arrive in America from Africa has caused a rush of interest in heritage tourism in West Africa, as descendants of slaves from America, the Caribbean and Europe visit ancient sites to delve into a dark and often hidden past. Picture taken July 17, 2018. REUTERS/Afolabi Sotunde