Since its arrival last October, Firaxis and 2K's Civilization 6 has launched a host of updates, a catalogue of player-made mods, and its Australian Summer DLC—which sees the land Down Under enter the fold for the first time in the entire Civ series. If you're yet to experience any of that, it's also now launched a free demo.
Downloadable via Steam, players who do so will assume control of China's Qin Shi Huang and play out 60 turns in charge of The Red Dragon. World domination can be levied by way of the Crouching Tiger Cannon, a ranged gunpowder unit; and the Great Wall improvement, where early game defence and gold transitions to culture and tourism—however you should consult Civ expert T.J. Hafer's full rundown over here.
Here's how T.J. summed up Civilization 6 in his review last year: "Sight, sound, and systems harmonize to make Civilization 6 the liveliest, most engrossing, most rewarding, most challenging 4X in any corner of the earth."
Alongside the free demo, 2K is running a Publisher Weekend Sale which will net you discounts on Civ 6's full release, as well as the likes of XCOM 2 and Mafia 3. More information on that can be found this way.