Why did ancient Greece create democracy?

The earliest civilizations of mankind: ancient Egypt, Sumer, ancient Babylon, etc. , appeared in about 3000 BC. But as soon as they stepped onto the historical stage, it was a centralized system and an imperial power system. Not democracy. The same is true of other civilizations.

It was not until the 6th ~ 8th century BC that the ancient Greeks first stepped onto the historical stage. They are city-states, and they are direct democracy, which is more democratic and direct than now. How can I put it? For example, if the Athenians want to decide an important event, they should call everyone to the square, discuss it together and vote by show of hands.

The most famous example is Socrates, who was put to death by 500 Athenian citizens. Socrates was executed because he "betrayed" the tradition of Athens and was a herdsman. In today's words, Socrates is a "herdsman". For a Greek who loves to think and argue, this person is really annoying ...)

This is the earliest democracy in human history. Today's western democratic systems all originate from this.