I am reading an alternative history trilogy by Kirk Mitchell called The Germanicus Trilogy. The series is based on two counterfactuals: Pontius Pilate pardons Jesus and the Romans beat the Germans at Tuetoburg Forest in 9 C.E. With these two changed events, the Roman Empire does not fall. It Romanizes the German tribes, who get incorporated into and revitalize the legions over the centuries. And without the martydom of Jesus, there is no Christianity and so the intellectual culture of the empire doesn't become intolerant and dogmatic. This prevents the social breakdown that contributed to the fall of the empire.
The stories take place in, as far as I can tell, the 20th century. The Romans have some modern technology, but they are far behind us. They have trains, guns and just recently mastered electricity.They have only just started to settle in the Novo Provinces (North America). The Aztecs have a formidable empire in Central America. There is some mention of a Chinese Empire as well. It has it's flaws, but it is quite interesting and entertaining. I've just started the second book. The Romans are about to go to war with the Aztecs.
I am fascinated by alternative history -- though I think it is hard to pull off in fiction. After all, you need a good story line, not just a gimmick. Nonetheless, it is endlessly interesting to imagine how the world would be different if one particular moment in time was changed. (What if Reagan died after the assassination attempt? What if JFK, MLK, RFK didn't die? What if Churchill had been in power instead of Chamberlain? )
Sometimes important world events hinge on the most coincidental or accidental events, so it's not hard to see how the outcomes might have been different. During World War I, Hitler had one of the most dangerous positions as a messenger on the front. He would have been under enemy fire often. And he was seriously wounded twice, once in a mustard gas attack. What if Hitler had been killed instead of injured? The last 70 years are completely different. Might WW2 never have happened? Would that have meant no cold war? No nuclear weapons? No Holocaust? What kind of impact would the hundreds of millions of lives that would have had an opportunity to grow and flourish instead of being extinguished have had on the world?
Or would someone worse than Hitler arise and precipiate these events, maybe even on a larger scale? Might a different leader have guided the Germans to victory?
It is imponderable, which makes it so intriguing!
I have my own pet alternative history. Indulge my fantasy. It centers around James J. Hill's Great Northern Railway (the only wholly privately funded transcontinental railroad--and also the only one not to go bankrupt). Hill with his Great Northern Railway and Pacific steamships facilitated a growing trade between China and Japan and the various states (New England textiles, southern cotton, Pennsylvania steel). After the (unjustified) trustbusting of Hill and federal requirements in rate-setting (and other market interferences), the trade with the Orient dropped off considerably. So here's the what if: the government doesn't interfere. China and Japan would have had significant economic ties to the US in the early part of the 20th century and forward. This might have also meant stronger cultural ties, with China and Japan developing more liberal economies and possibly more liberal politics. This might have prevented a communist China (and Korea and Vietnam?) and an imperialist Japan. There likely would have been a more robust economy, and so the great depression is only a minor and brief recession. No depression, no FDR, no new deal. Without a Pearl Harbor, the US might not have gotten involved in WWII; but if it had, its entire focus would have been in Europe and so the war there might have been over sooner. Imagine the lives saved! Imagine the fortunes made! The increased standard of living for millions upon millions of Asians and Americans. It boggles the mind...and really makes the damage of government intervention in the economy concrete.
One will never know how history would have played out, but boy is it fun to let the imagination run amok.