Viridian City is a small city in the Kanto region of the Pokémon universe. To the south is Route 1 which leads directly to Pallet Town. North of the city is Route 2 which contains the Viridian Forest and leads to Pewter City. Lastly, to the west lies Route 22 and the Pokémon League building.
In Pokémon Red/Blue and Yellow (and the remake Fire Red/Leaf Green) the city serves as the player's first destination after leaving their home town. Like every other major city in the Pokémon games, this city provides a Pokémon Center and Poké Mart as standard amenities.
Other primary points of interest include the Pokémon Academy (also known as the Trainer House in later games) where the player character can get useful in-game tips on the game mechanics, an old man which the player can coax into teaching them the mechanics of catching Pokémon, and the Viridian Gym. Although this is technically the first gym the player encounters in Pokémon Red/Blue, it is not accessible until the player has defeated the other 7 gym leaders in the region.