1) 4000 years ago, European and Middle Eastern built stone/brick palaces.
The Great Pyramid of Giza was built 4500 years ago.
3000 years ago, Yinxu, the capital of China was built by mud.
2) The Great Wall
The original Great wall (2000 years ago) as built by mud.
The Great Wall you see today was built a few hundred years ago.
Great Wall of China, Wikipedia
That's why Marco Polo did not mention the Greatt Wall at all.
3) When European live in caves, Chinese lived in mud holes.
It was long after the dinosaurs.