Points of departure that fall under this category are those which adopt a change that is not the result of a simple variation but rather the integration of a completely alien element to history from OTL. This element could be something which, according to modern mainstream science, is impossible or it could be the introduction of a fictional character(s) that has wideranging results.
Althistories in this category should not be confuse with secret histories which although might share some superficial similarities in term of background, are usualy assume to be taking place in OTL with the differences being hidden from us.
A sub-genre of this category would be "academic" counterfactualities, published works that use a non-historical point of departure to demonstrate an opinion, hypothesis or a statistical model.
A few examples follow:
- a form of magic is discovered during the Renaissance and takes the place of science.
- all of a sudden, every human beings turn purple.
- An explorer discover a gateway to another planet during the victorian era leading to a race for colonization by the great powers of that time.
- Writing was never invented.
- Gunpowder was never invented
- Scientific method never developed (or is developed much sooner than OTL).
- Technology developed which allows people to view and/or travel into other timelines.
- Aliens land on Earth.
See also
- Today in Alternate History a daily-updated blog, featuring "Important Events In History That Never Occurred Today" in several recurring timelines.