A zone in both Metroid and Super Metroid-- this is the lair of the Mother Brain, and the final area you must complete before completing either game. Decorated in a metal-pipe motif. Local enemies include the obnoxious rinkas and the regenerating zebetites, which must be blasted through to get to the end. Also the only place in Zebes where you will find the metroids themselves (the mocktroids in Maridia don't count.) In order to reach Tourain, Samus must first defeat all the minibosses.