The Battle of Somme:
https://en.m.wikipedia.org/wiki/Battle_of_the_Somme
What caused the German collapse:
https://www.thelocal.de/20181105/what-led-to-the-german-collapse-in-wwi
Truly amazing figures of how many soldiers died in the battle of Somme:
https://www.google.com/search?q=how+many+people+died+in+the+battle+of+somme&rlz=1CDGOYI_enUS705US706&oq=how+many+people+died+in+the++battle+of+somme&aqs=chrome..69i57j0l2.34428j0j7&hl=en-US&sourceid=chrome-mobile&ie=UTF-8
More on the Battle of Somme:
https://dailyhistory.org/Why_did_the_Battle_of_the_Somme_largely_fail_to_achieve_its_objectives%3F
Which ship sinkings cause the US to enter the war:
https://www.history.com/this-day-in-history/america-enters-world-war-i
https://www.google.com/amp/s/www.thelocal.de/20181105/what-led-to-the-german-collapse-in-wwi/amp
