Building tunnels that go underneath rivers in SimCity 3000

Contributor/author(s): Matt Fox

It's possible to build a tunnel that goes beneath a river. Just raise the elevation of the river temporarily to make a patch of land high enough to put a tunnel from one bank to the other bank. Put the tunnel in. Then you can go back and lower the elevation between the two entrances to the tunnels to make it a river again. You'll be left with one tunnel entrance at each shore and cars will continue to drive through it. You can tell the sims are actually going through the tunnel by placing residential zones on one side and industrial zones on the other. The zones will develop just as if a bridge connected the two sides. Otherwise with no connection between the two sides the zones won't develop successfully.

See also
Use marinas as powerlines over water
Building side-by-side tunnels
How to make a highway tunnel
How to build road or rail tunnels
Free up developable land with tunnels