Scrub away the lists, ladies.

This article contains far too many bulleted lists. These sections should be converted into normal prose.

Talk about it here.

An alien invasion was the process of any sapient species invading another planet and attempting to conquer or eradicate the natives.

Invasions of Earth Edit

Daleks Attack New York

The Daleks attack New York City in a rather stereotypical fashion. (TV: The Stolen Earth)

Many extraterrestrial species tried to invade Earth from the 20th to the 22nd century. Humans were a developing race; by sending space probes into space, they attracted the attention of more developed races. Organisations such as UNIT, the Torchwood Institute and the Department (which was created by aliens plotting to invade Earth) developed defences against these attempts. (TV: Spearhead from Space, The Christmas Invasion, TV: Regeneration)

Some of the most persistent species who attempted to invade the Earth include:

See also 21st century Dalek invasion and 22nd century Dalek invasion.

Other species that attempted to invade Earth include:

Several (if not most) of these were prevented (for the most part) by the Doctor in various time periods, (TV: The Dalek Invasion of Earth, The Invasion, The Unquiet Dead, The Christmas Invasion) but in the 21st century a group of neighbours and friends led by the Doctor's former companion Sarah Jane Smith did their part in preventing alien invasions. (TV: Invasion of the Bane, Eye of the Gorgon, Secrets of the Stars, The Temptation of Sarah Jane Smith et al.) While this group dealt with smaller threats, the larger invasion attempts were usually dealt with by the Doctor. (TV: Journey's End) Later in the 2050s, K9 Mark 2 became part of a group which safeguarded the Earth in the same fashion as Sarah Jane. (TV: K9)

Invasions of other planets Edit

During the human colonisation period of the mid-3rd millennium to the 51st century and beyond, humanity invaded various planets for their empires, including at least half of Mutter's Spiral, including Delta Magna, (TV: The Power of Kroll) the Althosian system (PROSE: The Pit) and many of the worlds in neighbouring galaxies such as the Andromeda Galaxy. (TV: The Ark in Space) The Vardans and Sontarans attempted to invade Gallifrey, the Doctor's home planet. (TV: The Invasion of Time)

Tivoli was the most invaded planet in the galaxy. It was inhabited by one of the oldest civilisations in the galaxy who simply let invaders do as they wished. Their anthem was "Glory to Insert Name Here" and their cities were designed to be comfortable for the invading armies

Motives Edit

There were many motives for alien invasion. Some species invaded due to the destruction of their homeworld, (TV: Terror of the Zygons, Rose, The Parting of the Ways, Invasion of the Bane, The Day of the Doctor, et al.) or the rendering of their homeworld uninhabitable, (TV: The Tenth Planet, The Seeds of Death, et al.) whilst others invaded to expand their empires. (TV: The Christmas Invasion, et al.)[additional sources needed] One particular case had the Earth invaded as part of a plan to power a weapon. (TV: The Stolen Earth / Journey's End)

The Sontaran Commander Kaagh believed the common reason was that humans had 'no guts', remarking that it was 'no wonder' that half the species from Earth to the Verlixix Spiral Cluster had plans to invade the planet. (TV: Enemy of the Bane) The Twelfth Doctor, after hearing from a human that there was a horror movie called Alien, commented that with that "really offensive" attitude it was "no wonder everyone keeps invading you." (TV: Last Christmas)

Some unknown power, organisation, or person had classed invasions by type. A type F invasion was said to be aesthetically motivated. (PROSE: The Well-Mannered War)