For Wonderlands×Showtime's Sekai see Wonderland Sekai.
Theme Park, specifically named Phoenix Wonderland, is a theme park in the real world of Project SEKAI owned by the Otori family. The Wonder Stage, where Wonderlands×Showtime work and perform, is also located here.
Majority of the characters have memories of visiting the theme park as children, and still visit it even now. This location contains various area conversations and is the setting for many main and event stories.