Crystal Tokyo is the future of Tokyo, Japan, set to exist within the 30th century. It is not only the capitol of future Japan but all of earth and is considered a utopia. Usagi and Mamoru rule the future under the names Neo Queen Serenity and Neo King Endymion. Both the anime and manga reveal this future, though the origins of both slightly differ. In both version, the queen and king are protected by the inner sailor soldiers. The status of the outer sailor soldiers is unknown, though Sailor Pluto guarded the time gates.
Crystal Tokyo formed when Usagi was only 22 years old in the 21st century. When Usagi ascended the throne and became Neo Queen Serenity, people ceased to age and began to enjoy extended lifespans due to the power of the Silver Imperium Crystal. Those born before the onset of Crystal Tokyo seem to be locked in at their current age, as most noted by the inner soldiers, still appearing in their late teens or early 20s. Anyone born after the onset will age incredibly slowly.
The princess of the new Silver Millennium was Chibi-Usa. After their awakening, the Sailor Quartet served as her own personal team.
Sometime during the early 21st century, the Earth underwent a massive world-wide freeze. The reasons for such a freeze is unclear. The effects of the freeze continued until Neo Queen Serenity awoke the world using the Silver Imperium Crystal. Together with Neo King Endymion, Serenity brought the Earth into a new state of utopia.
Peace continued for some time until the Earth was attacked by the Black Moon Clan from the planet Nemesis. Nearly the entire Earth had fallen to the attack, leaving Crystal Tokyo the only land standing. The sailor soldiers used all their powers to protect the city and Neo Queen Serenity.
From above, the city forms a 5-point star. Each point in the star was named a Crystal Point. During the present, members of the Black Moon Clan attempted to control these points in order to prevent Crystal Tokyo from ever forming.