If Napoleon beat Sir Arthur Wellesley, 1st Duke of Wellington, and the Prussians in the field at Waterloo then this would prevented Prussia forming the unification of Germany some 60 years later, and Germany/Prussia would never be the major continental power it was in our timeline. Thus, no WW1, which means no WW2 and it goes on. France would be the major power in Europe, Britain, her commonwealth and empire, the rest of the world (We lose every battle but the last).
If the Roman Empire didn't split into east and west it would of collapsed anyway, shit example on my part.
The Roman Empire converting to Christianity is possibly the sole reason for it's collapse. An 8th grader with a history textbook could work that out.
No christianity, no collapse, Roman dominance for hundreds if not thousands of years. Abrahamic faiths don't take off (Muhammad was clearly inspired by Jesus and Judaism [which he didnt like for some reason, selfish cunt]) which means Islam doesn't happen because the arabs would be ok with being pagans because they correspond with Greco-Roman gods, which is pretty universal like most pagan religions. Which means they won't fly planes into our buildings 1400 years later.

still in 9th grade .-.

also ur saying arabs fly planes into buildings?