The term Near Death Experience is a bit of a misnomer, many of the people who had 'NDE' were actually declared clinically 'dead' before making their return, however we will keep using the term for convenience sake and because being 'dead' often means one does not regain consciousness.
The reports have been similar over different cultures through different times and sometimes the person is able to bring back information he or she couldn't have known (like what the doctors were doing during the time you died, or a child knowing the names of passed family members they had never heard of etc.). The reoccurring theme is the following: - Seeing yourself float out of body - Seeing and speaking with dead relatives or other 'light beings' - Going through a tunnel into a white bright light - A life review; one experiences all the relevant moment in one's life and sees how your actions have affected others, you feel exactly how they felt and thought because of your actions. - Receiving a message that says: 'You are not done, you still have things to do and things to learn in from your life'.
Ultimately though, there are no 'non-physical realms', everything already is a mental construct, and the same experience of heaven or God, White Light, can be experienced during this life, in meditation, in stillness.
Being yourself, being loving, serving, being connected, is heaven.