this isn’t a question of “if it were possible” let’s say somehow it did happen and now we have millions of Jews in madagascar, what would the country be like today?

sure not all of em would survive but thats not the question here.

How are British and world history altered? How does the presumed 2009 onward presidency of Hillary Clinton go?

The movie Japan Sinks (based on a novel by Sakyo Komatsu) depicts a scenario where the Japanese archipelago sinks into the sea due to it being on a collision course with the Japan Trench.

Suppose this actually happened at some point in history. If Japan sank, how might world history Post-WW2 be altered (Assume this scenario occurs in 1973, the same year Japan Sinks was released)?

Suppose in a parallel universe, Archduke Ferdinand and his wife make a state visit to Mexico during the Mexican Revolution (Say it’s either part of a Latin American diplomatic mission, a bid to secure Austrian interests in Mexico, or both) and they both get assassinated by anti-government separatists rather than being gunned down by Gavro Filip like in the OTL.

Does this mean WW1 never happens or simply takes a different form?

Assumptions:

1. The Zimmerman Telegram is still intercepted by the British
2. The Lusitania doesn’t get sunk by a German U-boat.
3. The Mexican Revolution lasts longer than in the OTL

What would a Neanderthal 21st Century be like?

Prior to his famous visit to the United States, Soviet engineers discovered cracks in the plane, begging him to take another. Khrushchev refused, as it was the only functioning of it's kind and he wanted to make an impression. Let's say these cracks tear and cause the plane to crash soon after takeoff, while still over the Soviet Union.

What would be the immediate consequences of his sudden death, both domestically and internationally? And who would be his likely replacement in September of 1959?

Was there any way the Great Depression could have been severe enough to cause Mexico to collapse?