The only two things in the game that go obsolete

[Thalassicus]

This is not shown anywhere in the tech tree or civlopedia entries for the wonders or techs, nor does the city UI indicate a wonder you've built is obsolete. I stumbled across it when looking through the game files.

Navigation: Colossus.
Metallurgy: Great Wall.

 

[King Jason]

Colossus tells you on the tooltip when you go to build it that it goes obsolete.

Personally, I don't get why it even goes obsolete.

 

[bhavv]

Colossus is a weak enough wonder without going obsolete. It makes water tiles in just one city with a lighthouse as good as grasslands with a trading post.

Honestly, I see no reason to ever work water tiles in Civ V or build a lighthouse unless there are a minimum of two sea resources available to the city.

 

[oPlaiD]

Napoleon's ability goes obsolete with Steam Power.

 

[oPlaiD]

Colossus is a weak enough wonder without going obsolete. It makes water tiles in just one city with a lighthouse as good as grasslands with a trading post.

Honestly, I see no reason to ever work water tiles in Civ V or build a lighthouse unless there are a minimum of two sea resources available to the city.

Of course when there ARE sea resources, damn... put in a seaport and they are amazing.

 

[Willowmound]

I find it bizarre that walls and castles do not go obsolete.

 

[Trickster7135]

I find it bizarre that walls and castles do not go obsolete.

Castles I question as well, but walls are eternal. From the Berlin wall to Israel wall, modern times still warrant the use of walls.

 

[Willowmound]

Castles I question as well, but walls are eternal. From the Berlin wall to Israel wall, modern times still warrant the use of walls.

Not for military purposes, though. The walls you mention are for controlling civilians.

 

[Ahriman]

Collossus is definitely too weak to go obsolete. Worst wonder in the game.

 

[ShaqFu]

My guess is that the Colossus obsoletes at Navigation to prevent the possibility of Fish/Whale/Pearl supertiles with Seaports. I also suspect that, at some point, the Colossus did a lot more, because a 3/2/3 tile (fish) ain't that impressive. Even with a Golden Age, that jumps to 3/3/4, which is better (an an awesome tile), but hardly abusive, and at that point you're really getting into fringe cases.

 

[Mannu]

My guess is that the Colossus obsoletes at Navigation to prevent the possibility of Fish/Whale/Pearl supertiles with Seaports. I also suspect that, at some point, the Colossus did a lot more, because a 3/2/3 tile (fish) ain't that impressive. Even with a Golden Age, that jumps to 3/3/4, which is better (an an awesome tile), but hardly abusive, and at that point you're really getting into fringe cases.

It's situational. In my current game I have a city with 6 fish and also pearls. The Colossus + Market + Bank rocked my world.

And yeah, Seaport was amazing.