There is a lot of info on UB's but most of it is old from many years ago. I'm wondering what the current community thinks are the best UB's.
Here are the contenders that come to mind:
Terrace (Inca) - Granary with +2 culture is super duper useful to pop borders early
Ball Court (Maya) - Colosseum with +3 happy instead of +1. A useful build at only 80 hammers
Ikhanda (Zulu) - a super cheap 25 hammer Barracks that reduces city maintenance by 25%
Hammam (Ottoman) - Aquaduct with +2 happiness on top of the usual +2 health; useful in the biggest cities but costs 100 hammers
Dike (Dutch) - Useful in the late game as it makes coastal cities much better in production
Rathaus (HRE) - Courthouse replacement with -75% maintenance
Sacrificial Altar (Aztec) - cheaper 90 hammer Courthouse which reduces whip cooldown to 5 turns
Ziggurat (Sumeria) - cheaper 90 hammer Courthouse available with Priesthood
All the others are IMO either good only for cultural wins or super situational.
I'd probably go with Terrace at #1, Ikhanda at #2 and Ball Court at #3. Aztec UB feels very strong but I feel it's more situational and by 100 turns into the game you're probably doing lots of 3-pop whips which take longer than 5 turns to regrow from anyway. At that point in the game a normal 10-turn cooldown isn't too constraining. Maybe only in cities with absurd amount of food surplus you will get a good return. Rathaus and Ziggurat are definitely good but I wouldn't build them in every game. Ziggurat even though it comes earlier is on a weird Priesthood tech. Hammam misses out on top 3 as it's a bit weaker than the Ball Court and the Dike is helpful for sure but comes late in the game to matter much.
Here are the contenders that come to mind:
Terrace (Inca) - Granary with +2 culture is super duper useful to pop borders early
Ball Court (Maya) - Colosseum with +3 happy instead of +1. A useful build at only 80 hammers
Ikhanda (Zulu) - a super cheap 25 hammer Barracks that reduces city maintenance by 25%
Hammam (Ottoman) - Aquaduct with +2 happiness on top of the usual +2 health; useful in the biggest cities but costs 100 hammers
Dike (Dutch) - Useful in the late game as it makes coastal cities much better in production
Rathaus (HRE) - Courthouse replacement with -75% maintenance
Sacrificial Altar (Aztec) - cheaper 90 hammer Courthouse which reduces whip cooldown to 5 turns
Ziggurat (Sumeria) - cheaper 90 hammer Courthouse available with Priesthood
All the others are IMO either good only for cultural wins or super situational.
I'd probably go with Terrace at #1, Ikhanda at #2 and Ball Court at #3. Aztec UB feels very strong but I feel it's more situational and by 100 turns into the game you're probably doing lots of 3-pop whips which take longer than 5 turns to regrow from anyway. At that point in the game a normal 10-turn cooldown isn't too constraining. Maybe only in cities with absurd amount of food surplus you will get a good return. Rathaus and Ziggurat are definitely good but I wouldn't build them in every game. Ziggurat even though it comes earlier is on a weird Priesthood tech. Hammam misses out on top 3 as it's a bit weaker than the Ball Court and the Dike is helpful for sure but comes late in the game to matter much.