Marine Cave

Marine Cave, Hoenn (from Pokemon Emerald).

How to get here. Only after the Hoenn Hall of Fame. Talk to the scientist on the second floor of the Weather Institute on Route 119, or to the sailor in the Slateport harbor: they name a route where abnormal weather has started, and it lasts about 1000 steps. Marine Cave (Kyogre, level 70) shows up in downpour on Route 105, 125, 127 or 129. Once one of the two is beaten or caught, only the other comes up.