The virtual reality app “Pokémon Go” became a worldwide phenomenon in a matter of months. Now, Pokémon Go joins the Windy City for its anniversary and first annual festival, selling out Grant Park in minutes. Considered “the most successful mobile launch in history” by Superdata, it’s no wonder that the app is back for more—offering unique rewards and special features at its day-long event. Pokéstops offer eggs that can only be obtained in Grant Park, allowing users or “trainers” to encounter exclusive Pokémon. Users in Chicago work with thousands around the globe to complete challenges, unlock bonuses and add to one’s “Pokédex,” a trainer’s collection of Pokémon and their stats. If you don’t happen to “catch ‘em all,” enjoy a long walk in one of Chicago’s most beautiful parks instead.