The secret key is hidden in the basement of Pokemon Mansion which is located on Cinnibar Island.
The Secret Key that you get in the Pokemon Mansion is used to enter the Cinnabar Gym.
It unlock the door to the gym in Viridian City. .
to open the door of the 7th gym!
On cinnabar island but you need to get the secret key in Pokemon mansion first.
If you look carefully in the monean chamber and viapois chamber you can find a secret unown.
it's in the instruction booklet
You need the secret key which is found in Pokemon mansion which is also on cinnibar island.
seventh badge is cinnabar island. Fly to Pallet Town, surf south. Then go into pokemon mansion and find the secret key to unlock the gym
You have to find the key in the abandoned mansion.
You will find the key to the Gym of Cinnabar Island, From the Pokemon Mansion that is on the same island.
You will need to use the Secret Key which is hidden in the basement of Pokemon Mansion which is located on Cinnibar Island.
Be more specific