Djingis Khans grave
Djingis Khan and his mongolian army spread fear everywhere they go, today it would be called genocide. Djingis Khan conquerd a huge area from China to Poland. As a part of these conquests he also collected much treasures, no one knows what happened whit all the treasures but its likely that he got the most of it whit him in the grave.
Djingis Khan´s grave was going to be a secret so the slaves that dug the grave where exectued and the the slaves that exectuted the gravediggers where executed and so on, just to keep the grave a secret.
Where have searches been made?
Khan spent many long periods around his hometown Burkhan Khaldun, maybe its a good place to start looking.
Several expeditions have been searching for the grave, a couple of them even saying that they have found it, but haven´t produced any evidence for it.
Could it bee found?
If you know where to search for it, the odds is bigger then otherwise, but the chances are still slim.