Panama canal not in list of wonders?
I have all the techs prior to Panama canal researched. I have civics in Industrial era, although civics are not as advanced as tech tree.
For some reason the option to build it doesn't appear on my wonder list in cities. Are there any hidden requirements, such as oil (which I don't have as resource, although I do have Refining researched)?
Solution 1:
OP has already answered own question in the comments:
it's allright, turned out somebody else beat me to Panama canal
Someone already made the wonder, so it can't be built again.
Just posting here so the question can be answered.