It's unfathomable to me that the (kiln-fired, admittedly) mud bricks in these pictures are nearly unaffected after 1,500 years of being eroded by that river. >

It's unfathomable to me that the (kiln-fired, admittedly) mud bricks in these pictures are nearly unaffected after 1,500 years of being eroded by that river. > http://assets.atlasobscura.com/article_images/36872/image.jpg http://assets.atlasobscura.com/article_images/36872/image.jp... > http://assets.atlasobscura.com/article_images/36873/image.jpg http://assets.atlasobscura.com/article_images/36873/image.jp... > Even the river bed was diverted and channeled through the wall’s structures... Where the wall crosses a river, additional fortifications and dams were built to prevent covert infiltration by water. Bits of these fortifications still stand proudly, guiding the river’s course to this day. What are we actually seeing in these images? Have they recently been uncovered, or has the river course recently changed?