9th Edition: Urza's Power Plant
|Type:||Land - Urza's Power-Plant|
|: Add to your mana pool. If you control an Urza's Mine and an Urza's Tower, add to your mana pool instead.|
The Urza Lands are what give Tron its power. When you control all three types you can do some obscene things like turn three Karn or Wurmcoil Engine or turn four Ugin or Ulamog.