Two things happened today in the world of Sid Meier's Civilization that you should probably be aware of. First, the Fall 2017 update to Civilization 6 is now live, as is the Khmer and Indonesia Civilization and Scenario Pack, which 2K has recently been teasing. Second (and probably of greater interest), Civilization 3 Complete, which includes the Play the World and Conquest expansions, is free for the next two days on the Humble Store.
To claim your gratis game, pop over to humblebundle.com, click "Add to Cart" (right below where it says "Free!") and then follow your instincts: Buy more stuff, check out, whatever suits your fancy. You'll be rewarded with a Steam key for your efforts, redeemable directly through the Humble site, and you're off to the civic races. Bear in mind that it's only free until 10 am PT on October 21, so don't dawdle.