ignas, that's simply impressive! Still grasping for words... (the BC and early AD dominations and conquests are quite nice as well, but a 20K is always something special, and when have we ever seen one scoring 12000?!)
After this masterpiece I almost feel ashamed to report about my own attempt... But anyway, I also went for 20K (what else....). I tried a completely different strategy, not trying for a fast 20K date, but for a high score. So I outlined this game as a fast domination game + milking phase + 20K finish, and consequently used the first two towns for rexing and only the third town (founded next to the iron mountain east of the capital) as my 20K city.
Well, we'll never know, whether this was a valid strategy or just a stupid idea, because I ran out of time during the milking phase in 1255AD... The score at that point looked quite ok (3200 Fireaxis & Jason), but ignas probably even beat me in that regard, despite dedicating the capital to the 20K task... The 20K finish date is currently predicted at 1772, but there are quite a few wonders still to be build, so I think it would end up somewhere in the low 1700s.
Noteworthy is perhaps the unexpected usefulness of the Jaguars. First of all, thanks to TheOverseer's tip I used them as scouts and got very early contacts with our ten neighbors: in 1700BC I had ten contacts, the fastest scouting in any of my games, so far...
Next it proved very useful for the Jaguar -> Swordsman upgrade that I used in the beginning, before I had horses. Some of my towns were producing 7/8 spt, so were capable of spitting out Jaguars at the same rate as they would have produced ordinary warriors, but the upgrade is 20 gold less.
And finally even at later stages it should always be possible to find a red-lined Archer/Longbow somewhere to trigger a well-timed GA. In my game I did so in 320AD.
(And once an elite Jaguar even produced a leader for me...

)
Lanzelot