The cultural and social links between Ghana and Nigeria are therefore historically strong, and migration between the two countries has been taking place over the last 100 years. In addition to the economic incentives mentioned before, there were significant political incentives to immigrate to Ghana. Ghana was nominally independent as early as 1951,5 and adopted pan-Africanist political and immigration policies designed to attract other Africans to Ghana. Several later African presidents visited or lived in Ghana in the 1940s and 1950s, including those of Malawi, Nigeria, Sierra Leone, Zambia and Zimbabwe.