How do you open viridian city gym in Pokemon global revolution game?

To open the Viridian City Gym in Pokémon Global Revolution, you need to defeat the Elite Four and obtain the badge from the previous gyms. After that, you'll need to complete a specific quest or solve a puzzle that usually involves interacting with NPCs or finding items in the area. Once you've met the requirements, the gym will become accessible, allowing you to challenge the gym leader. Make sure to check any in-game announcements or guides for the latest information, as game mechanics can change.