For me it's Total War Rome 2. Set in Classical Antiquity, (300BC - 100AD) focused on Ancient Rome and the civilization around Europe, Balkans and Mediterranean around the time, you kinda play God as you control governments and make decisions for them.
There is so much to talk about and the game is so multi-faceted especially if you include the DLC and Mods around. The game is based on written and literary history around the time and as the name suggest, it's all about war.
The game divides into a campaign interface, where you move armies across the continent as well the government stuff. And the battle interface, where you "micro manage" platoons of armies in the battlefields.
There is just something about ordering squads of trained warriors around the field of battle from an eagle eye viewpoint and realizing this exact battle was fought thousands of years ago. Imagine that, me a regular guy wearing my pyjamas conducting a battle the way a great leader once did. They even made a show out of it! Look up Time Commander on BBC, the game engine is exactly Total War.