Being the long-sought source of the Nile, the region had long been of interest to Europeans. The first Europeans to arrive in the region in any numbers were missionaries who had limited success in converting the locals, but did open the region to later colonization. The increased contact with the rest of the world led to a series of devastating epidemics affecting both humans and livestock. While seen as a region with great potential after independence, the region has in recent decades been marred by civil war and conflict, which only Tanzania has escaped. According to the UNHCR, Tanzania hosted the most Congolese refugees of the region. The worst affected areas have been left in great poverty.