And now it's the endgame. Bismarck is still thoroughly friendly, so I've got absolutely nothing to worry about on the war front. England is many techs behind and I've barely got any border exposure to her. And I'm well on pace to hit the cultural win before anyone even gets to the modern era. This game is over, it just doesn't know it yet.
I'd continue research on Railroad, but then shut off the economy and run all culture. The other immediately available techs were Sci Method, Optics, Military Tradition, Fascism, and Combustion, none of which offered anything meaningful to the cultural victory. The second through fourth level techs available were Astronomy, Communism, Biology, and Physics, also all cultural blanks. Biology was hardly worth chasing, as I'd built maybe twelve farms total in my core cities, and they were all up against health limits anyway. And even with research at zero percent, all the free specialists could still research techs in ~20 turns!
I spread Buddhism around from my captured Spanish cities, which took some effort; even though introducing a fifth religion to a city should succeed at 65%, my missionaries batted about six-for-twenty. But eventually we erected all three Buddhist cathedrals. Judaism, my sixth religion, also came with the Spanish conquest, though that took long enough to bootstrap that I only ever built one Synagogue.
So here's a peek at each city's cultural production as we wrap things up.
Rome had built six wonders starting very early, which kept it well in the cultural lead all game.
Cumae had only one wonder, but harbored four settled Great Artists and the Hermitage, and had gotten the religious cathedrals done earlier as it hadn't been busy on wonders.
Antium had been a shield and wonder powerhouse, including three holy shrines, but all of that lacked the 1000-year doubling, and the city had arrived unfashionably late to the cathedral party (it's only got two even now.) This 279/turn culture is only temporarily low; by the end of the game it'd reach 901/turn thanks to four more cathedrals and 80% on the culture slider and "building" culture. It also received a Great Work around this time thanks to Rome's RNG favoring a Great Artist at 30% odds.
Now that's one religious city.
Now, there's still one more wrinkle to this game. See, the Adventure scenario has this little requirement that to be credited with a win, we must possess the largest army as defined by the Soldiers count in the demographics at game's end. I was currently sitting at 399000 as compared to Bismarck's 975000.
Since any game loss was now actually impossible, it mattered not at all what my cities built or did. So they built infantry. LOTS of infantry. Every city save my cultural laggard built nothing but infantry. Of the units available to me, Infantry provided the best Soldiers-per-shield ratio (20000 for 140.) It was a race between my military production and culture to beat Bismarck's soldier count before qualifying for the cultural win. Neapolis with the Heroic Epic and Ironworks would crank them at ludicrous speed, one per turn.
Presently, I gave Bismarck an extremely outdated tech (Liberalism) to attack Victoria. I was (delusionally) expecting him to whittle down his army some, but really that just made him build more. But the other goal of that move was to rebuild "common enemy" bonds between us just to ensure I'd never have to worry about him attacking me. And maybe distract him a bit from researching too, as his GNP was now exceeding mine.
Predictably, he called back a few turns later asking me to join in. I did but the war was entirely phony as I never fought a single English unit. Bismarck steamrolled over most of England, but made peace with two cities left and I did likewise.
I got very slightly worried when relations dropped to +9 with Bismarck as he caught up and passed me on tech (remember I'd shut off research). He converted to Christianity (!) after capturing some English cities with the religion. He said that too few of his people followed Confucianism to convert back, so I trained missionaries to send over... and discovered that he'd gone to Theocracy so I couldn't do anything there. But the worries were unfounded, as he never attacked me. He did demand one tech, which I gladly surrendered.
I had one more trick up my sleeve; if necessary to build the Soldiers count, I'd swap to Nationhood before the cultural win and draft like mad. Turned out not to be necessary, though.
Rome achieves Legendary Culture in 1852 AD, and Cumae follows in 1870 AD. Thanks to one last fortunate Great Artist spawn, I drop a second and final culture bomb in Antium, and on the very next turn after Cumae, Antium reaches the glorious milestone.
Cultural Victory in 1872 AD.