What is the Battle Tower?

The Battle Tower is a facility north of Route 40, near Olivine City, introduced in Pokémon Crystal as a first for the series: a structured challenge where trainers fight sequences of opponents under set rules, separate from the story's gyms and League. It is the ancestor of every battle facility that followed, the Battle Frontier of Emerald and the towers and subways of later games.

Crystal paired it with another debut, the first Move Tutor, and in Japan the Tower was wired into the Mobile System GB, so its challenges could be taken through the online service. In the Western release, with the network removed, the Tower simply stands open at all times.

Its placement matters to how Crystal is remembered. Gold and Silver's post-game was a second region; Crystal, on top of that, added the series' first repeatable endgame institution, the idea that after the credits the game becomes a sport with rules, streaks and records.

Every modern Pokémon post-game, the facilities, the ranked ladders, the endless battle modes, traces back to this one tower on the Johto coast.