Mt. Pewter

Mountain Pewter is a place that stands besides Pewter City. It is introduced for the first time in, while , and  visited there to look for Brock, the gym leader.

Part Red & Green
It is introduced for the first time in, when Redwald, Greta and Eusine could not find Brock at Pewter Gym, and were informed that Brock was in the area to solve a mystery. Thus, the group decided to look for Brock in the area. When they stepped to the area, they were immediately attacked by a bunch of Graveler and Golem. Right after, Brock appeared to save the whole group from them. As they explored, it was revealed that there is a cave in the area, in which a lot of wild Pokémon live. As Brock stated, the mystery was that occasionally the wild Onix would have been damaged. With the help of the group, Brock discovered that a bunch of rock was blocking the stream to flow, and the moss on the rocks would be stopped from growing. Therefore, the wild Graveler and Golem would feed Onix's moss on his body. Once they solved the mystery, they left the place.