From Bulbapedia, the community-driven Pokémon encyclopedia.
Victory Road is a tunnel situated on Route 23. It earned its name because it must be traveled by all trainers aiming for the top. It's other end opens up in Indigo Plateau and the Pokémon League of Kanto. Only trainers with all eight Kanto Gym Badges are allowed to enter it.
Victory Road has three floors. To reach the other end of the tunnel, a series of puzzles involving using Strength to move boulders need to be solved.
In Generation I, Victory Road is where the Legendary Pokémon, Moltres can be found. In Generation III, it's moved to Knot Island's Mt. Ember.
Some of the items found in Victory Road in Generation I include TM 43 Sky Attack, a Rare Candy, a Guard Spec., TM 05 Mega Kick, TM 17 Submission, a Full Heal, TM 47 Explosion, and a Max Revive.
Pokémon that Appear in Victory Road