Sky Pillar

The Sky Pillar is a huge tower located in Hoenn. Appearing in Pokémon Ruby, Sapphire, and Emerald, it is the only place in the game where the player can fight (and catch) Rayquaza. Many other species of high-level Pokémon also inhabit it, such as Dusclops and Altaria. The Mach Bike is needed to climb it, and is accessible in Ruby and Sapphire after the player defeats the Elite Four. In Emerald, it is accessible at any time with the move Surf and the Mach Bike.