travel to saffron city, fight the first gym and receive either hitmonchan or hitmonlee, then go to the company in saffron city, complete that, then you get rid of the rocket standing in front of saffrons gym, then the gym in viridian city opens
the gyms are in the citys but some are harder to get into than others
beat all of the other gyms first
They appear randomly like legendary pokemon's, if u have completed all gyms and elite fours.
I am not sure if you can.I have Silver and beat all 16 Gyms and never found a way to unlock the Safari Zone.:( Sorry.
They come like that. Each city which has a gym, the gym will open. But for saffron you have to finish silph co. Viridian will open after you have finished the other gyms. Cinnnabar will open after you have the key (i forgot its name) which you get in the Pokemon mansion.
Well, you have to defeat elite 4(they have pokemons between lvl.40 and 50 i guess).
viridian city gym. you have to beat all the other seven gyms to unlock this one.
If you have completed all the gyms, done the elite 4, gone to the other islands and completed those task, cached all the Legendre's (including mewtwo) then you start again
If you are referring to the first gym, in Viridian, you will have to wait until you have completed all the other gyms. There is a guide in the related links below.
Once you beat the other seven gyms, the final one will unlock. This is the same for Pokemon Red, Blue, Yellow [including the Special Edition] and Pokemon Red/Green.
Uh.. Pokemon Volcano? I never thought there were a Pokemon game like that...But you can find gyms in some city's,but not in towns.
The answer is... No there are no and i repeat NO hidden gyms on Pokemon soulsilver (but there are more gyms in kanto which you can get to by the boat pass from prof elm after you defeat the champion)