Bowser's Castle is one of Bowser's uncreatively named, yet decent looking castle. It's really warm there due to the lava and it is guarded well. Though some of the minions guarding are not really bright. Bowser's always working in making the castle harder to infiltrate, but little oversights end up making it easy. He's been working on trying to make the castle look more fearsome, but that never deterred Mario from coming to take the princess back from him. In a way, Bowser was also aiming to impress Peach. Due to the big difference in temperature and the ash and smoke that's in the air from nearby local volcanoes, there are lots of thunderstorms occurring here.