Did you know that Elvis didn't want to be burried underground and was the reason for him being originally buried in a masoleum?
When he was moved to Graceland there were talks of building a above ground masoleum, but the cost was too much for Vernon and the family to finance that they decided to bury him in a crypt.
Elvis' grave was dug out just like any other, six feet under, but instead of being covered with dirt as most are, the casket was placed inside of a thick concrete-like capsule and closed up, then dirt was placed on top of the capsule and the marker then on top of the ground.
So, if they were to ever dig him up one day, there would be no damage to the coffin or the remains. Elvis would still be intact.