If Humans Disappear

Found this video today by my fav Hashem Al-Ghaili. I found it quite astonishing so was thinking you might too. If this scenario happens within 10,000 years there will be no trace left by us except buildings made in stone. So, how do we really know then that the history we have managed to map out of our ancestors is true? What if i.e  20.000 years ago super intelligent beings actually lived on earth, all traces have just completely vanished? When that is said, no one knows when the pyramides were build, it's still a mystery, it could be 20,000 years ago. 

So what do you think? Are we the smartest civilisation ever to have lived on earth?

I do not believe so. But thats just me.. :)