Alternative histories are some of my favourite stories of speculative fiction. Taking a small change and extrapolating what might have happened differently is a fascinating mental exercise. For example, what would have happened if Christopher Columbus hadn't sailed west in search of a faster route to China? Or what would have happened if the Black Death had never swept through Europe and Asia? Or if Rome had remained a democracy instead of becoming an empire?
History is a fine balance between powerful social, economic and geographical forces and the choices of a few individuals poised in the right place at the right time to tip the status quo. I find the paradox fascinating. For the most part, the grand forces cannot be stopped, though they may proceed very slowly. As the Black Death killed a third to half of Europe's population, the available manpower for things like building and farming decreased. This led to people being more willing to try new techniques (leading to the Renaissance) and an increased value on individual human life (leading to the fall of the nobility and the feudal system). An increased interest in mechanical innovation eventually sparked the Industrial and Information Ages while the higher value on individuals would eventually lead to democracy over monarchy, women's suffrage and the civil rights movement.
There were (and are) many people who have tried to stop this inexorable process. They try to drum up fear and bitterness, pointing back at so-called "golden ages" and seeking to blame others for their own disappointments. But each generation becomes more accepting of the changes done by the generation before and pushes for further change.
And yet there are individuals who make a huge difference in the direction of the world. If there had been no Christopher Columbus, the countries of Europe would not have had the wealth of North America to fund centuries of battles and the civilizations of North America would have continued to develop. Contact would have eventually been made, but it might have been between cultures at a very different stage. If there had been no Augustus Caesar, Rome might have reverted to being a democracy after Julius Caesar was assassinated. There would have been no Pax Romana and no global Roman Empire, and very likely, no Roman Catholic Church. Would there have been a push towards greater equality and expanded Roman citizenship? Or would Rome have fallen into the forgotten annals of history as a failed experiment?
The individuals who make a difference are able to capitalize on the larger historical movements within their society. Columbus sailed on the wind of Spain's greed and religious and territorial aggressiveness. Augustus played on the Roman citizens' desire for a strong hand at the wheel and their fears of a drawn out civil war. But it is unlikely that someone else at the same time could have convinced the Spanish to abandon the Inquisition or Rome to see their conquered territories as equal partners.
To me, the fascinating part is how everything plays out. People make choices of their own free will, but are influenced by these huge patterns. Things can seem to change very quickly and unpredictably in the moment but then, as we look back, each step seems inevitable based on what came before It's a creeping tide of lines drawn in the sand by those who refuse to be pushed back.