Mew is Pokémon's first-generation Pokédex number 151. It is the final entry in the original Kanto Pokédex, following Mewtwo at number 150.
Mew is classified as a Mythical Pokémon and is associated with the idea that it contains the genetic ancestry of many other Pokémon. In the original games, it was not normally obtainable through standard story progression. Players generally received it through special distributions and promotional events.
Mew is often confused with Mewtwo because their names and lore are connected. Mewtwo is an artificially created Pokémon derived from Mew-related genetic material, while Mew is the naturally occurring Mythical Pokémon. Their neighboring Pokédex positions reinforce that relationship.
Although Mew was hard to obtain, it was still part of the original 151. Its position at number 151 helped make it a famous end point for early Pokédex completion and a memorable symbol of Pokémon's first era.