There is a phenomena that involves the bodies of thousands that refuse to naturally deteriorate. The people that fall into this category are called 'The Incorruptibles'.
Interesting enough, the Incorruptibles pertain only to Roman Catholic and Eastern Orthodox. There are no other incorruptibles that are part of any other religion. There have been mummies found that were Buddhist there were remarkably intact, however these bodies were found to be un-naturally kept in good condition.
One of the oldest incorruptible bodies that have been found, is St. Cecilia I believe, she was a Roman who was betrothed to a soldier and refused to marry him, instead wanting to be single and practice Catholicism, her father had her killed, she died in the first century, her body was discovered nearly 1500 yrs later and was in perfect condition, her head was still turned and separated from her body, both in perfect condition. Her body was last examined in the last 100 yrs and it is still in great condition, that is nearly 2000 yrs old.
Many of these bodies have what they call 'The Odor of Sanctity', meaning that the bodies produce a smell of fresh roses or perfume. These bodies have not been embalmed and in many cases are found in conditions that would lead to very fast deterioration.
Incorruptible Body Found in Coopersburg PA in 2001
This was a story that blew me away. In 2001 a convent was building a new medical wing onto their convent to take care of the aging nuns. They had to dig up old graves and move them. They came to the foundress, Mother Therese who had died 65 yrs earlier during Easter. The excavator hit her coffin and it burst open with a large quantity of water flowing out of it. Out of the break in the coffin, a white hand slipped out, much to the surprise of the workers. They ran to get help and when they pulled the coffin up, they found a perfectly intact Mother Therese, the palm branch that was in her hands when she was buried 65 yrs earlier, was still green! Her body was exhumed and the Vatican is currently reviewing her life to determine sanctity.
~Source - http://www.carmelite-nuns.com/Mother_Therese.htm
Incorruptible Saints
Below are a few saints that were found to be incorrupt:
Saint Alphonsus Liguori - (b. 27 September 1696 – d. 1 August 1787 )
Saint Joaquina de Vedruna - (b. April 16, 1783 – d. August 28, 1854)
Venerable Mary of Jesus of Ágreda - (b. April 2, 1602 – d. May 24, 1665)
These are just a few of the saints.. it's a beautiful phenomena and still baffles scientists to this day. It is a supernatural mystery.