Which structure currently operates as a "virtual fence:"  Boarder Wall or Mexico-United States Barrier?
Mexico–United States barrier The Mexico–United States barrier is a series of walls and fences along the Mexico–United States border aimed at preventing illegal crossings from Mexico into the United States. The barrier is not one continuous structure, but a grouping of relatively short physical walls, secured in between with a "virtual fence" which includes a system of sensors and cameras monitored by the United States Border Patrol. As of January 2009, U.S. Customs and Border Protection reported that it had more than 580 mi of barriers in place. The total length of the continental border is 1,989 mi .
Paso del Norte International Bridge The Paso del Norte International Bridge is an international bridge which crosses the Rio Grande (Río Bravo) connecting the United States-Mexico border cities of El Paso, Texas, and Ciudad Juárez, Chihuahua. The bridge is also known as "Paso del Norte Bridge", "Santa Fe Street Bridge", "Puente Benito Juárez", "Puente Paso del Norte" and "Puente Juárez-Santa Fe". The Paso del Norte International Bridge is a four-lane bridge for northbound non-commercial traffic only. The bridge was constructed in 1967. The American side of the bridge is owned and operated by the City of El Paso.