55-65
In Pokemon Emerald, Area 2 in the safari zone is available after beating the Elite. You get pokemons from the previous versions of the game.
You get some of the Jhoto region pokemons such as stantler, shellos, remoraid, etc.
with your pokemons
u must have the right pokemons yeah ;)
5-100
Beat the elite four the cave should open.
lightning and if that doesnt waork u just suck
beat the elite four get the pokedex and collect all pokemons
you should go look for the legendaries
there is no way in platinum but if you have other pokemons like emerald or ruby you can clone items like master ball or rare candy after you beat elite four and then you can migrate pokemons from them and give them items like master balls so you will many master ball in order to catch any legendary Pokemon
You can find legendary pokemons after you battle the gym leaders and the elite 4.
for emerald, raquaza, groudon, kyogre, your starter pokemon, magnemite and wailord.