The empires that did the most in my opinion, is the Assyrian empires. It is because they created the world’s first aqueduct, they use iron as their weapons material, and developed a new type of war tactics, siege attacks.
The reason why is because they developed aqueducts to help with water supply. It was a major help of those cities that does not live near rivers. The other reason was that the use of iron made their army stronger and more powerful, together, they were able to seize city with the siege attack tactics.
What will the other people say that does not agree with me, well, they might say that the Akkadians did more because they created the world’s first empire, and Hammurabi created the code of law, or Neo Babylonians made the world engineering masterpiece, hanging garden. Well, the 3 other empires did only about 2 contribution, but the Assyrian contributed 3 things to modern world, use of iron, siege tactics, and building the world’s fist aqueduct.
In the end, I just wanted to say that Assyrian contributed the most amount to the modern world because they did 3 key things, use of iron, aqueduct, and siege attack tactic.