The Great Wall was to protect against invasion by Mongols of the Steppe.

Mexico is already part of the US sphere of influence.

Fortifying the border wall and keeping many Mexican in a perpetual limbo, never giving them a greencard, is a strategy to drive divisions between workers, and reduce wages and harm work conditions.

There is a really simple and elegant answer. Thank you.

You know? You are right. I really couldn't get close enough to the wall to get really good pictures of it, but it is a blight at the very best. I wonder if the Chinese people felt the same about their wall?

It would be cool if you could get some drone footage of the wall so we could really see the extent of its size. I'm sure the Chinese were torn about the wall too, they just didn't have social media to complain and argue about it on a mass scale. Plus im sure it created plenty of work/jobs for them at the time, not that im sure it was paid for labour

The wall was built by slaves, and it's estimated that millions died to build it.

The Chinese were using the wall to fend off the Great Mongol Empire. China was the smaller empire. Eventually, it was incorporated into the Mongol empire, which extended from eastern Europe to the Korean peninsula.

If Mexico had a wall to prevent invasion by the US, it would be serving a similar purpose.

However, the US already has a lot of control over Mexico. Many of the presidents were educated in the US, or worked for American corporations.