Pokemon fans flood Grant Park for Pokemon Go Fest

CHICAGO, IL (CNN) - Thousands of people rushed to Grant Park in Chicago to be the best like no one ever was.

The Pokémon-Go Fest is back for its third year and some are already calling it the best yet.

Pokemon-go players are called "Trainers” who do their best to catch ‘em all.

To catch Pokémon on their phones they must interact with physical installations and complete activities in the park.

Tickets sold out quickly for the mobile gaming fest.

Tens of thousands of players from around the world are expected over the four days.