What are the top 5 longest lasting countries ever?

Answer 1

It entirely depends on how you define the term. Does it include countries whose dynasties change? Does it include countries that change their constitutions? Does it include countries that may have merged with other countries in the interim?

As a result, it is unanswerable. However, most of the longest lasting countries were the Ancient Empires. They had much more longevity than more recent states because of less technological and ideological changes over longer periods. Such empires include: ancient Egypt, the Persian Empire, the Yellow River Valley Civilization, etc.