The creator of BorderInvasionPics.com points out peaks atop the Huachuca Mountains, where individuals have been spotted surveying the U.S. Border Patrol agents below.
The cockpit of Spencer's single-engine Cessna TU206, as seen from the "jumpseat," aviation slang for an auxiliary seat for passengers not operating the aircraft.
Glenn Spencer, president and founder of American Border Patrol, returns his Cessna TU206 to a hangar at Bisbee Municipal Airport after a two-hour, 30-mile-plus trip along the border.
A Border Patrol agent's vehicle, center, is seen near the U.S.-Mexico border west of Sesabe, Ariz.
A network of trails are seen just across the U.S. border east of Bisbee, Ariz. The smaller, free-flowing trails are thought to be paths taken by human and drug smugglers.
A SBINet tower is seen in an area west of Nogales, Ariz. Surveillance towers like these are part of the Secure Border Initiative and use radar, motion detectors and long-range cameras to spot would-be border-crossers.
A portion of border fence separates the cities of Nogales, Arizona, to the north, from Nogales, Mexico.
The port of entry at Sesabe, Ariz., one of 327 official entry points into the United States, ten of which are located in Arizona.
Spencer discusses changes he'd like to see along the Arizona-Mexico border, including a complete, uninterrupted pedestrian fence similar to those found at California's San Diego and El Centro border sectors.
A portion of border fence near Nogales, Ariz., one of several urban areas along the Arizona-Mexico border where fencing is primarily used instead of vehicle barriers, which are utilized in more remote areas.
Glenn Spencer, president and founder of American Border Patrol, gives FoxNews.com an exclusive look at smuggling corridors along the Arizona-Mexico border, alongside the creator of BorderInvasionPics.com, which publishes pictures of illegal immigrants entering the country.