You have to beat all of the other gyms otherwise it's impossible.
Giovanni
Head back to Viridian City and challenge the gym there (it will be open now) to get your 8th badge. After that come the Pokemon league.
you must beat all other gym leaders
It is atchrily the 8th gym. It will open when you get the first 7 gym badges
After u beat the first 7 u will go back to pallet town and then go to viridian and the gym that was earlier locked is now open (Giovanni is the boss)
Dugtrio, Rhydon, Nidoking, Nidoqueen, Rhyhorn.
The 8th gym in Pokemon Yellow is situated in Viridian City. It is the second city you encounter when you first begin your game.
the 8th gym is closed because you have to beat all other 7 gyms and then it will be open p.s. the 8th gym leader is giovonni
Wallace is the 8th gym leader PEOPLE!!!!!!!!!!!
You need to have defeated the other seven first. Once you have, you'll be able to get in. It's a Ground-Type-based gym, and the leader is Giovanni.
In the 8th gym. he is the gym leader
In Pokémon Yellow, the 8th Gym Leader, the Viridian City Gym Leader, Giovanni's Pokémon are Persian, Dugtrio, Nidoqueen, Rhydon and Nidoking. Persian is at Level 53, Dugtrio at Level 50, Nidoqueen at Level 53, Nidoking at Level 55 and Rhydon at Level 55.