Death is an experience of transition that gives the illusion of an ending, the illusion of finality,

and the illusion of separation.   

Nothing is ever annihilated.

It may be broken down (as in decay) into it's constituent parts, losing it's original identity but always gaining a new one. 

In the case of human beings, some of our constituent parts stay on the earth plane

(our carbon, for instance)

and some (soul/spirit/consciousness),

now freed from the density of matter, go on to exist in a higher dimensional plane. 

                          We do not die.  We just change form.

It's just that simple.