Sky Pillar Rayquaza - English - Project Pokemon Forums

In the games Pokémon Ruby & Sapphire, Rayquaza can be caught in the Sky Pillar during the post-game. In the game Pokémon Emerald, Rayquaza can be captured right after the Groudon VS Kyogre battle, which in this instance it can be encountered right before the player defeats the Elite Four.

Dragon Ascent (move) - Bulbapedia, the community-driven Pokémon

Road to Legendary - Sky Pillar by Urusee584 -- Fur Affinity [dot] net

Sky Pillar - Bulbapedia, the community-driven Pokémon encyclopedia

Rayquaza Redemption I, Pokémon Wiki

Sky Pillar Encounter by Ikikurumi on DeviantArt

Sky Pillar's Rayquaza - XY & ORAS - Project Pokemon Forums

K.W.C.E. #12 - Rayquaza vs. Monster X - Toho Kingdom

Sky Pillar's Rayquaza - XY & ORAS - Project Pokemon Forums

Rayquaza, Pokémon Wiki