Homo sapiens, over the past 300,000 years, have historically died from three causes:
disease, famine, and violence. Modern humans have successfully battled all three.
Disease is suppressed by hygiene, waste water management, and vaccinations.
Mechanized farming and mass distribution have all but wiped out famine (modern
famines are generally man made). Nuclear weapons and the threat of total
annihilation have limited violent wars to local skirmishes.

This gallery deals with hygiene.