A pair of rubber boots?
In the room before you actually enter the great marsh, go up the stairs. There will be binoculars in the upstairs room, you can use them for $100.
You need to Migrate Pokemon from the PC boxes from GBA Pokemon games then you can enter the great marsh. if you have the DS I. You can't do it. I hope i answer your question? so if you don't migrate Pokemon from: FireRed LeafGreen Sapphire Emerald RubyEtc. you can't enter the marsh (Catching show thing)
use the HM move defog (you can get it from the the guy at the great marsh and when you enter the great marsh go all the way to the right and talk to the ace tranier)
No, the Great Marsh is in Pastoria City on D/P/Pl but you have to beat the Gym leader first before you can enter. The Gym leader is "Crasher" Wake and he uses Water types.
the great marsh is in Pastoria City
great marsh great marsh
The HM for Defog is located in the Great Marsh of Pastoria City. Just enter the Marsh and talk to the Cool Trainer right at the entrance. He'll give it to you.
the great marsh is in Pastoria City
There is no cave in the Great Marsh.
in the great marsh in the great marsh
talk to people in the great marsh
The Great Marsh, is located inside the Pastoria City.