this is an AATL inspired by the feedback to my earlier experimental attempt
https://www.alternatehistory.com/discussion/showthread.php?t=263926
The premise of the timeline is that the period between the Crimean war to the Russo-Turkish war (1853-1878) punctuated the century of relative peace Europe enjoyed between the end of the Napoleonic wars and the first World war. This period witnessed six wars involving one or more of the great powers (Crimea, German-Danish, Franco-Austrian, Austro-Prussian, Franco-Prussian, Russo-Turkish) resulted in the consolidation of both Germany and Italy into great powers and thereby fundamentally changed the balance of power achieved at the first congress of Vienna- but without overturning it completely.
Concurrently with these European wars two massive civil wars were fought in the United states and China (American civil war 1861-1864, Taiping and Nian rebellion 1850-1867) which OTL very nearly drew the Europeans in (Trent affair, French invasion of Mexico, second Opium war) but in which their involvement was ultimately marginal.
in this time line a butterfly flaps it's wings, and one small change leads the various localized conflicts to be conflated into a single global conflict. The period leading up to the outbreak of the second Napleonic wars should be critiqued by the standards of plausibility rather than probability. I don't think that the most likely outcome of the POD I am proposing would be a global war that early (though a European war in the 1870s or 1890s is highly likely) but it's sufficiently plausible and interesting that I am interested in plotting it out.
So, having said that what is the POD?