Terra Cave

Terra Cave is a cave where Groudon lives in Pokemon Emerald where can be located at Route 114, 115, 116, and Route 118. How to find out where this cave is located is by talking to a scientist on the top floor of the Weather Institute. You can only do this method by defeating the Pokemon League. Listen to the scientist say "Presently a drought was at Route 114, 115, 116, or 118. If you aren't quick enough, you will have face over Kyogre, but if you are in the Terra Cave, then you won't be too late and stay there for as long as you want. If you catch or faint Groudon, and you exit the cave, you won't be able to visit it again.