BARRIERS BUILT TO CONTROL HUMAN MOVEMENTS HAVE A LONG HISTORY
FIGURE 5.16 The border fence between the Spanish city of Melilla and Morocco is intended to reduce illegal migration into Spain from Africa. The border fence between the United States and Mexico is intended to reduce illegal migration into the United States along its southern border.
(Blasco de Avellaneda/AFP/Getty Images) (Frederic Brown/AFP/Getty Images)