Pokemon GO is finally getting legendary Pokemon, and the first one is set to appear at the Pokemon GO Fest event in Chicago's Grant Park. Niantic did not announce exactly which legendary Pokemon would show up at the event, but the company did say how fast the rest of the world will see legendary Pokemon all depends on what happens at Grant Park. Should the amassed players at the event manage to defeat the legendary Pokemon that shows up, they'll all get that Pokemon for themselves, and it will begin appearing worldwide, kicking off the rollout of legendary Pokemon. Niantic has not announced how the rollout will be handled if the Grant Park crowd doesn't win, but that's fairly unlikely given the size of the event and the demand for legendary Pokemon that the company has been bombarded with since the game came out.
Legendary Pokemon work a bit differently from normal Pokemon in a number of ways. For starters, legendary Pokemon won't appear on the streets as catchable like a normal Pokemon; the only way to get them is by defeating them in raid battles. When a legendary raid is going to start, qualifying players will get an invitation 48 hours in advance showing them the time and place that the legendary Pokemon will appear. Legendary Pokemon are far more powerful than normal raid Pokemon. Another difference is that if players manage to beat the powerful Legendary and get their own, it won't leave their side; that means no leaving it at gyms, and most likely no trading it away, once that feature eventually rolls out.
The event in Grant Park is the culmination of a celebration of Pokemon GO's first anniversary that has been going on since late June, and included events both in-game for all players, and out in the real world. Players who want to talk about the event can do so using the #pokemongofest hashtag on social media, and those who want to see the game's first legendary Pokemon appearance and the subsequent battle streamed live can do so on Twitch and YouTube. You can find links to those live streams by heading through the source link. Tune in to those on July 22 to see it all go down live.