“Effective June 1, 2009, all citizens of the United States, Canada, Mexico, and Bermuda must carry a passport or other accepted documentation when entering or leaving the U.S. by air, land, or sea. This requirement — known as the Western Hemisphere Travel Initiative — has been gradually implemented since 2007 to allow sufficient time for travelers to obtain proper documentation. Visit this U.S. Department of Homeland Security webpage to see what types of documentation are accepted.”