SAN YSIDRO, CA - JANUARY 8:  Pedestrians wait in line to enter the United States at the border in Tijuana Mexico from the United States January 8, 2007 in San Ysidro, California. Beginning on January 23rd, United States passengers traveling by air will be required to show a passport when traveling to Mexico or the Caribbean. Congress is also pushing to require passports when traveling by land or sea to from the United States to Mexico or Canada by early 2008. Getty Images logo Getty Images 34 months ago

SAN YSIDRO, CA - JANUARY 8: Pedestrians wait in line to enter the United States at the border in Tijuana Mexico from the United States January 8, 2007 in San Ysidro, California. Beginning on January 23rd, United States passengers traveling by air will be required to show a passport when traveling to Mexico or the Caribbean. Congress is also pushing to require passports when traveling by land or sea to from the United States to Mexico or Canada by early 2008.