Crystal Tokyo (クリスタル・トーキョー) was the new name given to Tokyo of the 30th Century. It became not only the capital of Japan, but also of the entire Earth. It was a utopia, the epicentre of the new Silver Millennium, at the center of which stood the Crystal Palace.
In the anime, the city formed the shape of a five-pointed star when seen from above. The five locations which formed the points of that star were known as Crystal Points; various members of the Black Moon Clan tried to take contol of those points in the past on Earth in order to prevent Crystal Tokyo from existing in the future.