After getting the HM (Hidden Move) "Surf", you explore the Kanto region's waters, and meet a variety of aquatic Pokémon. Eventually, you come across a bunch of small, uninhabited islands, known as the "Seafoam Islands". The largest island has a cave that goes very deep underground, the cave having temperatures below freezing, as well as a multitude of Pokémon that have accustomed to the frigidity of these cave. A gentle, soothing whistle is heard, coming from a very deep part of the cave. Curious, you descend down the various levels of the cave, until you see the Legendary Bird Pokémon, Articuno. She stops whistling, and looks at you, albeit with no agression, unlike most Legendary Pokémon.

"Hello, traveler."