Let's say that you had the chance to watch any one funeral in history. Likely, most people made that offer, after they stop wondering what the hell kind of offer is that, would probably take someone of religious importance.
Nobody, if they were smart, would pick Genghis Khan's. (Yeah, you see, there was a point to that opening.)
Genghis died in 1227 outside Mongolia, and wanted to be buried there. That narrows it down very little, as this was Genghis Khan's Mongolia, which as you know was absolutely ginormous, reaching out as far as northeastern Iran. He also wished to be buried in an unmarked grave, which was preselected and preprepared. However, he was considered a god, so a lot of people wanted to pay their respects. But you didn't want the place looted, and there was reportedly a lot to loot, including, among other things, the crowns of each of the 78 rulers Khan had toppled.
How about they just kill everybody?
About 2,500 slaves were in the funeral procession, alongside 400 soldiers. As the legend goes:
*Anyone or anything that just so happened to be in the path of the funeral procession was killed.
*The funeral itself saw 40 virgins killed as sacrifices to allow Genghis company in the afterlife.
*40 horses were also killed, presumably in case there was something to conquer there. Virgins and horses were tossed into the tomb.
*At the close of the funeral, all 2,500 slaves were killed by the soldiers.
*When the soldiers returned from the funeral, they were killed.
So now nobody knows where the tomb is. To this day, nobody's found it, and only in recent years have archaeologists begun to THINK that they MIGHT be in the NEIGHBORHOOD, and attempts to locate it are frequently frustrated by locals who would prefer the tomb not be disturbed on fear that it would damage the soul within. Efforts are frustrated further by the rumors that a river was diverted over the gravesite, or possibly a forest created and grown on top of it.
Well, maybe not nobody. One baby camel did survive, so that Genghis' family could be led to the site. How would the camel know? They killed its mother. But even then, the family would have to be blindfolded, because if they knew where they were, they'd have to be killed too. (Never mind what that 2004 link says about maybe finding it. They didn't.)
The only way one might know where it is would be to have been at the funeral. But, as the saying goes, then they'd have to kill you.