At the beginning of the game, you go into the first city and find out that the gym is
locked. After you finish the gym on Cinnabar Island, the gym at Viridian City (that first
city) should be unlocked and is the eighth gym. It's filled with lots of fighting/ground
types.

Helo, there! So, when you have won seven badges, you will have too fly to viridian city
where the gym, near the old man, will finaly be open... Who is the gym leader, find out
yourself! The leader will have moastly fighting and ground typs, so i would recomend usind
water typs, fire typs, grass typs or even poison typs. Not only is the final gym leader
here, but alot of martial art trainers are here too! You will encounter the following
trainers:

1)black belt's pokemon:
Machoke (level: 38)
Machop (level: 38)
Machoke (level: 38)

2)tamer's pokemon
Arbok (level: 39)
Tauros (level: 39)

3)black belt's pokemon:
Machoke (level: 43)

Cooltrainer's pokemon:
Nidorino (level: 49)
Nidoking (levle: 49

Also there are others! Remember, you may not like battaling but you could earn (with the
same pokemon) around 5 levles better!
Also, here is the gym leder's pokemon:
1) leader giovanni's pokemon:
Dugtrio (level 50)
Persian (level 53)
Nidoqueen (level 53)
Nidoking (level 55)
Rhydon (level 55)

Yes the strange leader is the rocket boss, . Also, you will find the following items:
1)revive (on floor)
2)tm27 (gift from giovanni)

The final badge, is called the 'earth badge'. Earning the earth badge allows you to use
hm08; rock climb outside of battle. Hope i helped,
Flaffy11 ;)

P. S for more info check out serebii.net!!!