Pokémon Go Fest will take place later this month to celebrate the game's first birthday, and those attending in Grant Park, Chicago on 22nd July will need to work to unlock a "major global reward" for everyone else playing.

But what could it be?

First, players in the park must capture Pokémon of specific types to unlock worldwide rewards - XP or Stardust boosts, for example, or reduced egg distances.

If attendees catch enough to unlock the event's bronze or silver medals, then the effects will be extended worldwide by 24 or 48 hours.

If attendees catch enough to unlock the event's gold medal tier, then the main Mystery Challenge will unlock.

Starting at 6-7pm Central time (midnight-1am back here in the UK), the Mystery Challenge will allow players in Grant Park to... do something. Developer Niantic has not said what, but if it's not capturing the game's first Legendary Pokémon then everyone is going to be very upset.

Successfully completing this will then unlock the major global reward - presumably, the release of said Legendary/Legendaries worldwide - in a 48-hour event from 23rd-24th July.

And then finally I will have a chance to see a Legendary Pokémon and then have it run away from me.

Additionally, in mainland Europe, a series of events will take place in shopping malls across the continent. These events, dated for August and September, will unlock Pokémon region exclusives from other countries for capture.

5th August, 2017

Fisketorvet - Copenhagen, Denmark

Centrum Cerny Most - Prague, Czech Republic

12th August, 2017

Mall of Scandinavia - Stockholm, Sweden

Stadshart Amstelveen - Amstelveen, The Netherlands

16th September, 2017

CentrO - Oberhausen, Germany

Les Quatre Temps - Paris, France

La Maquinista - Barcelona, Spain

Specifically in the UK, some sort of event is taking place in Chester on the same day as Pokémon Go Fest in Grant Park, Chicago, but there's no word on any exclusives being there. Shame!