Several different means of smuggling, such as cross-border tunnels, are used to bring narcotics, individuals, and contraband into the United States. Cross-border tunnels can be found all along the land border of the United States. They vary significantly in size and complexity of construction, although most are crudely constructed. Further, most cross-border tunnels are used for smuggling narcotics, although illegal aliens and other contraband have also been smuggled using tunnels.From the information given above, it cannot be validly concluded that