Joe Biden is using the first visit to Angola by a U.S. president to promote Washington's hefty modern investments in the sub-Saharan Africa nation and to see a slavery museum where he'll acknowledge how the trafficking of human beings once linked the two nations' economies. A centerpiece of his trip is showcasing the U.S. commitment of $3 billion to the Lobito Corridor, a railway redevelopment linking Zambia, Congo and Angola that is meant to make it far easier to move raw materials around the continent and for export. The project also has drawn financing from the European Union, the Group of Seven leading industrialized nations, a Western-led private consortium and African banks.