25th century

In the 25th century, the planet Earth, under a repressive government, had a population of a hundred billion people, most of them living on floating islands. It was a highly polluted planet. (DW: Colony in Space) Most Earth colonies during this time were "terrible places." (NA: Christmas on a Rational Planet)

Schooling was quick. Students obtained certificates in a vast range of disciplines by the age of ten. They were taught by machines for one hour a week. In comparison, a 20th century high school was like a nursery. (DW: The Web Planet)

Both Vicki Pallister and Nikki Jupiter, companions of the First and Tenth Doctors respectively, were natives of this century.

Prior to this century, World War IV was fought on Earth. On a visit to London in February 1814, Vicki noted that St Paul's Cathedral survived not only the four World Wars but the 22nd century Dalek invasion. (CC: Frostfire)

Some other cultural tidbits of the 25th century included:
 * The Beatles were considered "classical music", and a theatre dedicated to them existed in Liverpool. (DW: The Chase)
 * Aspirin tablets were no longer in common use. (DW: The Web Planet)
 * Humanity travelled in hyperspace. Such journeys were common and commercial. (NSA: Judgement of the Judoon)