Greetings All,
I've often wished I had the ability to build a bridge or tunnel to cross short spans of water without having to use a ship to load and unload units across. There's lots of potential for Firaxis here; different technology levels and all. If this word can get out to those making Civ4, I hope you'll add this ability. Perhaps if enough of us jump on the bandwagon we can make it happen.

I think it's a great idea.

And some sort of automation to make units cross water should also exist! If you play an island world this can be boring!

welcome to CFC [party] (I'll have to find a new welcome message someday)

I agree to tunnels under one tile water if there is an effective way to stop an abusive use of them.

Ive got an exam on tunnelling in a week! Oh wot fun.
A one space sea tunnel is probably the same length as the channel tunnel. It'd probably have to take at least 20 years to build and only be available sometime early in the modern era. Also you'd have to own the land at the other side of the sea or a friendly neighbour who agrees to help build the project (it'd have to be built from both ends). All in all its probably a bit too complex and doesnt really give any amazing benefits for the game.

Maybe tunneling isn't plausable before the Modern ere, but bridges sure are. I think that being able to build bridges would be a great improvement, as crossing a one or two tile stretch of water with an army (not an army unit, just a lot of troops) can take 15 minutes or so at the moment. My concern would be when it comes to ships wanting to get up and down the stretch of water? Sure, in the modern era bridges have been known to be lifted for Tall Ships, but not Medieval esq. bridges. Oh, and another thing-what happens if your crossing the bridge and two enemy ships attack from each end, severing your connecton with the land? That could be costly if you have a 4 or 5 MA Army units sitting up there...

Bridges to span rivers have been around for ages. But the bridges needed to span gaps as big as one sea tile (i.e. the size of a city)? The engineering required for that has only been around about the same amount of time (at least in civ terms) as tunneling has.

With the current teleportation type railroad transport building bridges/tunnels to extend ure railway system would make airports obslete. Theres got to be some way to recognize that travelling across spans like that is going to be far quicker by air.

If the railway system was changed then i can see a use for tunnels/bridges. Though im still not 100% it's worth putting them in

It needs careful implementation but it can be done.

welcome to CFC [party] (I'll have to find a new welcome message someday)

I agree to tunnels under one tile water if there is an effective way to stop an abusive use of them.
Agree, I do not wish to see the same abuse of underwater tunnels as seen in Call to Power I and II.

The worst thing that could happen is if you can go from a tunnel to another. This would be horrible.