Over 2000 years ago, using Iron-Age tools, the Chinese built a 5,500 mile wall to protect their northern border from the Xiongnu. Today, the United States of America, the richest and most advanced country ever to exist, cannot build a 2,000 mile fence along our southern border? Bullshit! It is more than justified, as the Mexican Cartels are far more dangerous than any Xiongnu nomads. Let us build the Great Wall of America, I say! Our grandchildren's grandchildren will visit it, as a historical site, a wonder of the world!