Mortality.
History shows that if you can get this message across to people, you can get a really good
religion started.
And like it says in the Mahabharata:
- The yaksh asked, "What is the most surprising wonder of the universe?"
- Yudhishthira said, "In the world of human beings, everybody sees that many, many people are dying daily. The wonder is that he thinks that his turn will never come."