Yamaraja asked Maharaja Yudhisthira, ‘What is the most wonderful thing within this world?’
Mahārāja Yudhisthira replied (Mahabharata, Vana-parva 313.116):
ahany ahani bhutani gacchantiha yamalayam sheshaḥ sthavaram icchanti kim ashcaryam atah param
“Hundreds and thousands of living entities meet death at every moment, but a foolish living being nonetheless thinks himself deathless and does not prepare for death. This is the most wonderful thing in this world.”
"Everyone has to die because everyone is fully under the control of material nature, yet everyone thinks that he is independent, that whatever he likes he can do, that he will never meet death but live forever, and so on. So-called scientists are making various plans by which living entities in the future can live forever, but while they are thus pursuing such scientific knowledge, Yamaraja, in due course of time, will take them away from their business of so-called research." - Srila Prabhupada
Every minute and every second we experience that living entities are going to the temple of death. Men, insects, animals, birds—everyone is going. This world, therefore, is called mrityuloka—the planet of death. Every day there are obituaries, and if we bother to go to the cemetery or crematorium grounds we can validate them. Yet everyone is thinking, “Somehow or other I’ll live.” Everyone is subject to the law of death, yet no one takes it seriously. This is illusion. Thinking we will live forever, we go on doing whatever we like, feeling that we will never be held responsible. This is a very risky life, and it is the densest part of illusion. We should become very serious and understand that death is waiting. We have heard the expression, “as sure as death.” This means that in this world death is the most certain thing; no one can avoid it. When death comes, no longer will our puffed-up philosophy or advanced degrees help us. At that time our stout and strong body and our intelligence—which don’t care for anything—are vanquished. At that time the fragmental portion (jīvātmā) comes under the dictation of material nature, and prakṛti (nature) gives us the type of body for which we are fit. If we want to take this risk, we can avoid Krishna; if we don’t want to take it, Krishna will come to help us.