I just had a brilliant, and sad, idea. What if we changed two things about history? What if the Nazis were not driven by fanatical racialism, just German nationalism, and what if they won WWII?
The second part is easy to imagine, it very nearly happened several times, but Hitler was chronically disposed to snatch defeat from the jaws of victory. Britain could have been knocked out in the first month at Dunkirk, or starved out if one stupid pilot didn't drop his magnetic mine on a sandbar and let the British get a hold of it, Rommel could have driven his tanks all the way to Persia, took all the oil Germany could have ever needed, and started a massive rebellion in India to cripple Britain, and Moscow could have been taken had Hitler not sent Army Group Center all over Russia on a wild goose chase.
The first part is more difficult to imagine, but I'm allowed one break from reality in this counterfactual and that's the one I'm taking. In my scenario there is no Holocaust, just revanchist Germans who want to reclaim their place in the sun.
The first consequence of this scenario would be there would be no Cold War. There would be no clash of East and West, no rise of communism in China, no Korean War, no Vietnam War (the Japanese might have faced some trouble, but they probably would have just slaughtered people until the rebellion died down), no nuclear arms race. What about a war between Germany and Japan? What war? A cold war would mean technological parity, and that just did not exist. The Japanese were very good at copying things, but they were terrible at coming up with new designs on their own. The Japanese Zero fighters which were shooting down American planes left and right in 1941 were rendered useless by American innovations like the Hellcat and the radio proximity fuse. As long as the Germans don't give their technology away then the Japanese would not get nuclear weapons, not for many decades, at least.
And neither would America. If the Nazis do not drive out the Jewish scientists as they did in our timeline then all the greatest minds in the world would still be in Germany.
Whether the Germans would have developed an atomic bomb during the war is hard to tell. They might not have needed one. Assuming they were working on all the advanced science projects in the new timeline as in ours, then at the very least they would have developed something called "Virus House", which was a bomb filled with plates of enriched uranium separated by kerosene, which acts as a neutron absorber. The bomb was supposed to be dropped over Britain at a few places (London, Scapa Flow) in the water where the force of impact would send the uranium plates crashing into one another setting off a chain reaction that would contaminate the water an spread radioactive steam over a wide area. These were not nuclear bombs in that they would never go critical, they would be like miniature Chernobyls. Had there not been a German brain drain before the war they really could have come up with their own Fat Man, maybe drop it on Stalingrad if need be, depending on where their timeline diverges from ours.
Another consequence of this scenario would be routine space travel. You could imagine taking a rocket plane from Berlin to Tokyo in 3 hours. Germany was working on something they called the "America Rocket", which was a 2 stage man-piloted rocket that would fly all the way around the world and deliver a kamikaze nuclear attack on New York City. They were also developing something called the "Mars Rocket". I'll let you guess what that project's destination was. When you consider that German rocket technology is what was behind both the US and Soviet space programs, it's not difficult to imagine the Germans getting to space all on their own after the war ended. One can imagine the Germans landing on the Moon by 1955 and reaching Mars by 1980. By 2016 there would be permanent colonies on both the Moon and Mars, and maybe a floating colony on Venus (Venus' atmosphere is so dense that a capsule filled with regular air at 1 Earth atmosphere pressure would float like a balloon). Using nuclear pulse rockets a 50-year mission to the nearest stars would have been launched and might even be half way to its target. A two generation crew would be on board, with the future scientists who would do all the exploration leaving Earth as infants to be taught by their parents on the way. Most of the adult crew would likely be dead by time the ship reached its destination, and the babies would now be 50 years old. It would necessarily be a 1-way trip, but there was no shortage of people willing to die for the Fatherland.
What would happen beyond that is harder to imagine.