Don't pop huts with units, unless you don't have any attack/defense units. Instead, pop huts by planting cities next to a hut or let an AI pop a hut.
Use the 2nd city for wonder building so that you can use the palace to prebuild. Germany doesn't have good position early on, because they don't start with Alphabet, nor Masonry. Actually, with this map it could be best to move the settler to the 2-1 (keyboard strokes) from the starting position, and put the first city there. Then the 2nd city can go in place where it sits, and then it has the best shield position we know of, and a quite good spot for production.
The palace prebuild starts at 300 shields. Since this is a standard map, you need 14 cities to get the palace cost up to 400 shields, and 17 cities to get the palace prebuild up to 600 shields. So, it could help to conquer some AI cities early to get that prebuild up, if/when you run out of territory to settle. The Heroic Epic has high value in a 20k game also. 4 culture per turn for 200 shields makes for a very good ratio. That all said, since the cost factor is 6, the AIs pay 60% of what you do for wonders. So, like The Sistine Chapel (perhaps one of the hardest wonders to build at high levels), only costs them (.6 x 600) = 360 shields to build. Thus, if you started The Sistine Chapel with a complete palace prebuild of 300 shields, you would have the advantage to build that wonder. The issues though lie with the cascades from Sun Tzu's Art of War or Leonardo's Workshop can mean The Sistine Chapel can disappear quickly. Still though, there might not be any cascades for J. S. Bach's Cathedral. And a 300 shield prebuild would mean you have fewer shields to go when the AIs could actually starting building J. S. Bach's Cathedral, if you started it on the same turn.
As long as you can build all of the regular cultural buildings early, The Heroic Epic at some point, and some other small wonders, you either have enough culture to win 20k by 2050 AD or end up close. If close and you didn't snag any medieval wonders, I think industrial era great wonders and some modern wonders would do also, if you got there fast enough. But, the AIs either need controlled or killed off so that they don't win the game also.
But, IF you focus your city on making some cultural build as much as you can, you either need no or a small amoun of great wonders to win a 20k by 2050 AD, as Sirpleb showed a long time ago when he timed out a 2050 AD 20k victory exactly. Bartleby also did so recently. His cultural builds we can show in two pictures:
And that's it. No library, university, or colosseuum. The Colossus giving 3-6 culture per turn gives as much as a library. But, a library costs less. A Colosseum gives as much as Knights Templar. And a colosseum can come sooner. A university gives as much culture as The Oracle.
So, we need to make the 6-12 culture from The Great Library and the Museum of Mausolos. Heroic Epic + Wall Street gives 4-8 + 2-4 culture per turn. The Apollo Program produces 2-4 culture as the Museum of Mausollos does. O. K. the Apollo Program might never double in culture not getting built before 1050 AD or too close to 1050 AD. However, we're still in the ballpark with no great wonders at all. So, if we can get some great wonders along the way... hopefully some nice medieval wonders and then all three industrial wonders or at least the modern wonders, then getting enough culture by 2050 AD seems achievable.
Edit: forbidden palace + intelligence agency + strategic missile defense + pentagon can probably make up the culture from the palace.
Oh, also, I would advise against building The Miltiary Academy in one's 20k city. If you need/want armies, they probably need to come from elsewhere. If you get to a good position later, you can just abandon the city with The Military Academy and then put it in your 20k city.
AND I forgot the research lab too...
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