Kaifeng, used to be the capital of China during 7 dynasties. It lies directly on the bank of the yellow river, and was destroyed many times by the flood. The tradition was, old town would not be digged out, but new town would be built on the base of the old town. Therefore the Kaifeng city today is not the old capital any more. But people talk about it all the time: "Kaifeng has 7 old cities under its feet..."
This is also the reason why it is not allowed to build high buildings in Kaifeng today, because their weight will probably destroy the historical site under the ground. Today only in the Qingmingshanghe Park, you can see a bit how the old capital looked like.