The Mongol Empire was the most contiguous empire of all time, and Genghis Khan was its founder and ruler. The Silk Road was able to thrive because of this empire, which stretched from the Pacific Ocean up to Ukraine. Khan was also instrumental in establishing reliable postal service, paper currency, and diplomatic immunity. His death occurred in 1227 CE. His successors conquered even more land.
You would expect that such a large figure would have monuments and amazing tombs to commemorate his life. Perhaps similar to the pyramids of the Taj Mahal or ancient Egyptian pharaohs? It would be a mistake to say otherwise, since little is known about his death and very little about the exact location of his tomb.
Many stories surround his death. Many believe he was injured while fighting with Chinese troops and fell from his horse. Some believe he was killed by a Western Xia princess, who inserted a device into her vagina. Khan slept with the girl, and he was castrated. This theory may be due to his enemies, who wanted Khan to be vilified.
Most of these rumors are believed to have been conjured up by his family after his death. His followers and relatives were told to keep the truth secret. This secrecy was primarily due to the fact that death occurred at the worst possible moment - a crucial stage in the Western Xia conquest, which was 20 years in progress.
His death could have been considered more medically-historical in that he suffered from unwellness between August 18th and August 25th 1227 CE. He was then reported to have died 8 days later.
The army may have ridden 1,000 horses over the grave in order to remove any trace. The secretive location would have rendered physical investigations and grave-robbing impossible.
Some people in Mongolia would prefer to keep it secret. Khan is revered by some, while others respect the fact that Khan wanted it to remain secret.
Folklore and one theory suggest that the tomb may be located in the mountains of Khentii on Burkhan Khaldun. Khan is believed to have once fled from his enemies and vowed to return in his death. This is still controversial. There are evidence to suggest that five other mountains were once called Burkhan Khaldun.
Scientists have been trying to use modern technology to locate the locations. PLOS ONE published a paper that attempted to use crowdsourcing (more than 10,000 volunteers online who contributed 30,000 hours) in order to locate Genghis Khan via a satellite search. They searched 6,000 km2 (2,316.6 mi2) for the tomb but did not find it.
We may never find the tomb. Perhaps it should be preserved that way to honor his last wishes.