Worlds longest wall

[Robert W]

Built from the third century BCE to the 17th century CE in order to keep out northern invaders, the Great Wall of China is considered the world's longest wall, extending a total 13,170 miles. Although our mental image of the Great Wall is probably one of a continuous structure winding its way across China, the reality is different. The Great Wall is actually composed of various stretches of wall and watchtowers — often with gaps between. There are even areas where the wall is non-existent. The original builders also made use of natural barriers to keep invaders out. As much as a quarter of the wall's length relied on features like rivers and mountainous ridges to keep the marauding hordes back. Today, much of the wall is in ruins, but sections that date from the Ming Dynasty (1368–1644) can still be seen.

 

[MaryL]

Built from the third century BCE to the 17th century CE in order to keep out northern invaders, the Great Wall of China is considered the world's longest wall, extending a total 13,170 miles. Although our mental image of the Great Wall is probably one of a continuous structure winding its way across China, the reality is different. The Great Wall is actually composed of various stretches of wall and watchtowers — often with gaps between. There are even areas where the wall is non-existent. The original builders also made use of natural barriers to keep invaders out. As much as a quarter of the wall's length relied on features like rivers and mountainous ridges to keep the marauding hordes back. Today, much of the wall is in ruins, but sections that date from the Ming Dynasty (1368–1644) can still be seen.

Unfortunately, it didn't keep out the Mongols. I get your point.

 

[HereWeGoAgain]

That fits with our Southern border wall.
They dont build walls along the Rio Grande where it's cliffs that are almost impossible to climb without experience as a rock climber.