I'm not sure where you find views on the new board - I don't necessarily miss them but I can see why some would.
Anyway, in post-1900 it's really tough, but let me take a crack at it.
In 1900(or early 1901 if that's considered to be the before 1900 board), an Olympic organizer, seeing the way the world comes together for the Games, thinks it's a good idea to bring world leaders together the same way. A bunch of the strongest imperialists and globalists get together and decide they should meet in 1906. Since there is so much debate over which European city would host, with the 1904 Olympics in the US such a hit, it is decided that San Franciso would be used. "It's equidistant from everyone - it's the middle of nowhere" is the joke, even though San Francisco is becoming a major city by this time, hampered only by its being on the West Coast of the US.
A variety of bombastic speeches by leaders like Wilhelm II of Germany and also by globalists like Woodrow Wilson are made, but then, the Great Earthquake strikes. Suddenly, Germany, Russia, and several other natiosn are without their leaders. William Howard Taft, preresenting the US government, also dies.
So, instead of continuing to ramp up its military, Germany starts to stand down, while the Russian Empire also sees more sane leadership. as many of the most powerful nations lost their rulers or people high in government, there is a period of mourning that brings them closer. While there are a few small wars in the Balkans, the assassination of the Austrian Emperor in 1911 (there was a major plot OTL) fails to lead to a major war, instead Franz Ferdinand takes over and, while Serbia must pay indemnity, they crush the Black Hand while he federalizes things. A revolt af ew years later leads to more of a British-style Constitutional Monarchy.
Meanwhile, in the US, William Jennings Bryan has won a narrow victory in 1908 with TR's handpicked man not very good, and TR comes back and wins in 1912. (See my "
Setting Down Root" TLIAFD) He uses all his might to get Social security and other things through Congress, and without Wilson's racism, things slowly improve, as TR continues to meet with Booker T. Washington and others to promot the "talented tenth," figuring helping them will trickle down to the rest. It doesn't totally help, of course, but world travel has increased a lot, and people are starting to understand other cultures a little more.
Such travel means that the huge influenza outbreak impacts much of the world. James B. Cox, Ohio's governor, is not killed by it, but he is weakened to the point he dies early in his term - after about ten months in office. Franklin Roosevelt succeeds him, but he often jokes that, like his distant cousin Theodore, he will be seen as one of the great Presidents despite not having been elected at first. Some are upset at the idea of TR having won in 1916 as well and then having a Franklin Roosevelt so early in 1922, but others say that at least he is from the other party, and FDR promises not to run in 1928. He expands helps that will mean the Depression isn't as severe in 1929, and famously does quite a bit for blacks hurt in flooding in 1927, but the latter, and even somewhat the former, led to the reactionary John nance garner being elected in 1928.
Some said it was the best thing that could have happened.
the Democratic party split between Conservatives and Progressives, with FDR drafted as a candidate even though he didn't want to run, and the GOP mopped the floor with them. A series of progressive-minded Republicans, who were only concerned with keeping waste out of government, beginnign with Alf Landon in 1932 ran the country.
There were international problems, of course. The West, Russia, and even the isolationist US protested when Japan invaded China in 1937, and eventually, they realized they needed to step in. when in 1939 Japan attacked South. Thomas Dewey in 1940 brought the US into the war, which lasted from 1940-1942 (I'm calling this equal to the Golf War - remember, on a larger scale it is very similar at this point to the world mobilizing after Iraq invaded Kuwait) before Japan was surrounded and bombed into submission.
Franklin Roosevelt had been a key part of putting this coalition together, and Dewey even applauded him and suggested that he should put together a global organization. The United Nations is founded to end the evils of racism and bring countries together - the problem of racism in Japanese culture had been very apparent, and one of the points in their charter, pushed especially by Eleanor Roosevelt, is that treatment of women in ways the Japanese ddid with Koreans must be abolished.
Race relations improved more and more in the US; baseball was integrated in the early '40s, and Jesse Owens - hailed as a hero for his smashing victories in the Olympics in 1936 and again in 1940 - is seen as the catalyst. Indeed, one writer famously noted that, "The 1940 Summer Olympics were seen as the final calm before the storm - the time in which the nations of the world got their rest in before they would all go to war to defeat the Imperial japanese."
Okay, that's all I have time for, but I think an outline has been laid which can allow things to continue with a largely peaceful tone throughout the next 75 years to the present of TTL.
(Edit to add - the 1940 Olympics were to be in Tokyo OTL, in TTL they swap places with Berlin, with Japan hosting the 1936 Games and Germany 1940.)
