Nknknknk City

You can't do the Gym before you do the Team Nose Hideout.

After you beat the Gym, a group (named "Qz") of people tries to take you to Gtharej City, which eventually leads to the city with the next gym, since you can't get there on foot except through Ghough City, since there's a wall to the east of Nknknknk City preventing people from going to The Snus, but you get left in The Snus, east of Nknknknk City.