Niantic released a snazzy trailer featuring the Legendary Birds from the first two generations -- Zapdos, Articuno, Moltres, Lugia and Ho-Oh -- as well as a blog post, explaining these majestic creatures will sporadically appear within the game's Gyms.
"As Trainers around the world go out and explore their neighborhoods in search of Pokemon and Raid Battles, they can keep an eye out for unique Legendary Eggs appearing at Gyms," the post reads. "If Trainers and their team are able to successfully defeat a Legendary Raid Boss, they'll have the opportunity to catch a Legendary Pokémon of their own!"
The festivities will kick off this weekend at Chicago's Grant Park, where Pokemon Go Fest takes place. If players catch enough Pokemon, Niantic said, the first Legendary Pokemon will be revealed, and will be available in Raid Battles globally.
Absent from the teaser video were Mew or Mewtwo, who will likely be special events unto themselves, given their status as OG Pokemon. The legendary dogs found in Pokemon Silver and Gold -- Raikou, Suicine and Entei -- are also conspicuously absent.