US Customs and Border Protection Process

OTAY MESA, CA - MARCH 6: A view of warehouses along the U.S.-Mexican border shows the buildings where a 1200 yard long drug smuggling tunnel was recently found entering an empty US warehouse on March 6, 2006 in Otay Mesa, California. DEA, Customs and Border Patrol (CBP) and Immigration and Customs Enforcement (ICE) officials claim tons of marijuana and cocaine were moved through the tunnel as well as where possible human smuggling occured. Otay Mesa, California is one of the busiest US ports of entry with direct highway access to San Diego and Los Angeles. The San Diego, California sector comprises 66 miles of land border with Mexico. This is a popular crossing area for Mexican human smugglers. (Photo by Robert Nickelsberg/Getty Images)