Location from Sailor Moon by Naoko Takeuchi / Toei Animation
The future Earth in the 30th century — a utopian city ruled by Neo-Queen Serenity and King Endymion, currently under assault by the Black Moon Clan when Chibiusa arrives from it.
Crystal Tokyo is the world Usagi is going to build. She doesn't know that yet when she first sees it, which is an interesting position to be in. It is frozen and besieged when the present-day Guardians visit — Neo-Queen Serenity is unconscious, her power sealed by the Black Moon Clan's Black Crystal, and King Endymion is managing the crisis holographically from a damaged body. Chibiusa came from here. She came because she trusted that her parents — who at this point in her timeline are fictional historical figures — would help her if she could reach them.
A gleaming city of white crystal spires centered on the Crystal Palace, where Neo-Queen Serenity lies in a deep sleep brought on by the Black Moon Clan's attack. The city has the beauty of something that was meant to last forever and is currently in crisis.