You have to find raquaza. Then raquaza scares groudon and krogoe ( or something ) away. Then, you can get into the gym.
Water.
You find him in the last Gym in Sootoolis City.He is the last Gym leader
Help me
Pokemon league
The Fortree gym.
there is no gym at pacifidlog
Defeat all of the Gym leaders on Emerald. ~KKMG1
there is no gym in slateport, the next gym would be in mauville with electric pokemon
In Pokemon Sapphire, Ruby and Emerald the 7th Gym that's located in Mossdeep City has Psychic type Pokemon.
In 7th gym
fortree
at the gym