Q: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Where is Genghis Khan buried?, Context: Years before his death, Genghis Khan asked to be buried without markings, according to the customs of his tribe. After he died, his body was returned to Mongolia and presumably to his birthplace in Khentii Aimag, where many assume he is buried somewhere close to the Onon River and the Burkhan Khaldun mountain (part of the Kentii mountain range). According to legend, the funeral escort killed anyone and anything across their path to conceal where he was finally buried. The Genghis Khan Mausoleum, constructed many years after his death, is his memorial, but not his burial site.
A:
close to the Onon River