Looking for a Great Tower Defense game

There was a "game mode" on one of the earlier Warcrafts that was what I think is a "Tower Defense" game.
Basically, creeps spawn every so often and you build your towers and upgrade them to prevent them from getting through.

What made that Warcraft version so much fun was that:
1) it was multiplayer. one on the left, one on the right and one at the center to clean up any that passed through the left or right
2) it was a 3D version with a wide corridor that allowed people to build pathing defenses instead of the typical 2D versions you typically see (zombies charging at castles (verticle 2D like angry birds), or ants getting to some candy in the middle (horizontal 2d like a chess board).

I was hoping somebody remembered that Warcraft version and/or could point me in the direction of something similar.