Lumiose City

Bubbly Basin is a new area introduced in the first pack of the Pokémon Pokopia Expansion Pass and is an area that is primarily underwater. It is based on a sunken Cerulean City including iconic areas such as Nugget Bridge, Cerulean Cave, Cerulean Gym and Bill's House There are several hidden locations within it including Misty's room behind the gym, an underwater lab at the bottom of the sea trench and a Coral room near the temple