go to the elite 4
After getting all the badges the 8th gym will open You beat givoanniORWalk Through Walls!!!!!!!!!!
The eighth badge can be obtained by defeating the gym leader in viridian city.
Beacon Badge
the boulder badge from brock
The last gym leader is the boss rocket to get him to the gym beat team rocket at: Mt moon, Game corner, Pokemon tower, Silph co. After you do this get the 7th badge if you haven't then you can get the last badge in viridian city.
The 8th Badge in Pokemon Diamond is called The Beacon Badge.
Head to Cinnibar Island for your next badge.
Do you mean the elite four? There is a total of eight badges in Pokemon LeafGreen. Thus, the eighth badge is the Earth Badge, which you obtain after defeating Giovanni in the Viridian Gym. Giovanni uses mostly Ground-type Pokemon with a few Poison dual types. Persian and Arcanine are the only exceptions to those.The Eighth gym is located in Viridian City, it is automatically unlocked once you defeat Blaine (provided he's the 7th you've defeated). So basically fly to Viridian City.
earn it.
You have to beat the eighth gym leader to get to the Elite Four. Without defeating the eighth gym, you cannot get the S.S. Aqua ticket. You also cannot capture Lugia without the eighth badge.
fuschia.
Fuschia city.