What's the highest possible adjacency bonus?

[evonannoredars]

I realised recently mountain wonders provide double adjacency bonuses to culture/happiness buildings, since they're both wonders and mountains. Hoerikwaggo is especially powerful as it alone can give a +6 adjacency to a building in the right spot, which got me thinking - what's the highest possible adjacency you can get?

I assume the game automatically sorta evenly distributes wonders somehow, so two next to each other is unlikely. But Hoerikwaggo (+6), a tropical mountain with Macchu Pikchu (+2) and mountains or wonders in the two remaining adjacent tiles (+2) could result in a +10 adjacency.

Is there anything that could get a higher adjacency, for any kind of building?

 

[Yzman]

As Isabella when I was putting happiness buildings near a mountain wonder I think it gave me 23 happiness...

 

[Menocchio]

If you have a coastal island surrounded by water tiles, you can get +6 adjacency for Food and Gold buildings; wonders that can be placed on water, like the Colossus and Statue of Liberty, effectively double the adjacency bonus of their tile (from +1 to +2), giving +7-8 total.

Alternatively, Meiji Japan gets a tradition card that gives Military buildings an adjacency from water tiles—so you could place one of those on that same island and it'd be even higher if there are sea resources adjacent to the island. There are also some other adjacency bonus traditions that could contribute to really high numbers, but I've forgotten most of them besides the Abbasids' adjacency bonus for all buildings with the Palace/City Hall and Nepal's adjacency to Food and Science buildings from mountains. Theoretically you could double that on Food with Pachacuti? It'd still just be food though, not a hard-to-get yield.