From Bulbapedia, the community-driven Pokémon encyclopedia.
Mt. Pyre (Japanese: おくりびやま Mt. Sending-off Fire) is a location in Hoenn. It has an interior and exterior section and is located on Route 122.
Mt. Pyre can be considered a counterpart to Kanto's Pokémon Tower and Sinnoh's Lost Tower. It houses the many graves of Pokémon. Many grieving trainers also visit the Tower to pay their respect. Also present within the mountain are thrill seeking trainers who will battle the player when they come across them.
An old couple that live on the summit of the mountain are well versed with the legends of Hoenn. They guard the Red Orb and Blue Orb that are sought by Team Aqua and Team Magma.
Depending on the game version, Team Magma and/or Team Aqua will attempt and succeed to steal the Orbs from the summit of Mt. Pyre and use them to awaken Groudon or Kyogre. After the player has subdued the legendary Pokémon, the player can return to the summit to watch Maxie and Archie return the Blue and Red Orb to its proper place.