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. (TV: Colony in Space) Most Earth colonies during this time were "terrible places." (PROSE: 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. (TV: 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. (AUDIO: Frostfire)

Around this time, an Earth expedition led by Professor Parry was trying to uncover the lost tombs of the Cybermen on Telos. There they discovered that the Cybermen, contrary to popular belief, had not gone extinct, but instead gone into frozen hibernation in their huge underground tombs. One of the members of that expedition, Eric Klieg along with his accomplice Kaftan, aimed to use the Cybermen's strength, coupled with their intelligence from the Brotherhood of Logicians would transform the Earth Empire into a new power. His plan fell apart and eventually the tombs were sealed shut, supposedly forever. (TV:  The Tomb of the Cybermen) Some other cultural tidbits of the 25th century included:
 * The Beatles were considered "classical music", and a theatre dedicated to them existed in Liverpool. (TV: The Chase)
 * Aspirin tablets were no longer in common use. (TV: The Web Planet)
 * Humanity travelled in hyperspace. Such journeys were common and commercial. (PROSE: Judgement of the Judoon)

After arriving in London 2167, the First Doctor, yet to determine which point in time they were, told Ian Chesterson and Barbara Wright to bear in mind that they might have landed in the early 1900s or the 25th century. (TV: The Dalek Invasion of Earth)