You'll have to wake Snorlax, and head down to Fuchsia City on cycling road.
This way, you will enter the city from the west. When you continue down the road, you'll eventually see the roof of the Gym.
Once inside, there'll be a maze, made up from nearly invisible walls. Go right, up and left to reach the back wall of the gym. There is the entrance of the maze, where you'll reach the Gym leader. The walls are slightly visible. Use Psychic or Ground type Pokémon to have the biggest advantage against this gym.
fuschia.
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in Viridian city. the one that was locked.
You don't need a badge to get strength but you need a badge to use strength and that badge is the rainbowbadge and that is the 4th one in celadon city.
the one you get from the gym in fuschia city.
fuschia.
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You must beat team rocket at Pokemon tower and the rocket hideout then get the 5th badge.
the boulder badge from brock
Fuschia city.
In Vermilion city.
Head to Cinnibar Island for your next badge.
vermillon city
Vermilion city.
In cerulean cities gym you must beat the leader misty to get the cascade badge.
Articuno is in Seafoam Islands you need the HM Strength to get to it though and the HM Surf also you need the 4th and 5th badge.
Open the door and challenge the gym leader.