Pokémon FireRed & LeafGreen: Got the Poké Flute — Pokémon Tower
What opens up at this point in the game, and everything you can catch by now that you couldn't before.
✓ You get the Poké Flute once you rescue Mr. Fuji at the top of Pokémon Tower, where the ghosts need the Silph Scope from the Rocket Hideout. The flute wakes the Snorlax blocking Routes 12 and 16, and the same rescue makes the Silph Co. door guard in Saffron City stand aside.