I vote for "The Great Wall of America".
-18" thick
-Steel reinforced concrete
-Give a differnet contractor responsiblity for every 5 mile section, giving out TONS of work to US Citizens ONLY...
-20ft tall, 10ft deep
- small sentry tower every 1000M with sharpshooters to prevent people from digging and climbing.
- 3 border Gates, one East(Laredo/ Nuevo Laredo), one Central (Presidio/Ojinaga), one West (Nogales), controled by the US military.