Mexico-US border

Along the border between Mexico and US there is a fence, 7000 kilometers long. The fence is an American government initiative and the cost of construction and maintenance amounts to several billion dollars since 2006. Its purpose is to restrict illegal immigration and drug trafficking and to protect against terrorists. The Mexican-US border is one of the places in the world where the difference between rich and poor is most apparent. It is just a few steps between richest abundance and deepest poverty.