Their homelands are torn by war, economic distress, political strife, or environmental collapse. They choose to leave, or have no choice. They're called migrants, refugees, or internally displaced people. The labels are inadequate as often circumstances could allow all three descriptions, or some combination of them. Once in their new countries, they face difficult transitions, discrimination, or outright hostility. Host countries are burdened with the economic and political repercussions of the arrivals, while home nations are sometimes saddled with a "brain drain" of their most important human resources. Immigration is a hot-button issue in the American presidential race, and a wave of new arrivals from Libya to Italy has left the European Union struggling with decisions over the Schengen policy of borderless travel between member nations. Gathered here are images of some of the estimated 214 million people worldwide in the process of redefining what "home" means to them. -- Lane Turner ( 47 photos total