I’m not sure about you question
I'm not sure what specifically you're referring to when talking about what changed in 1926 so here's a resource for you that has a bit of information about what was going on in 1926.
http://www.thepeoplehistory.com/1926.html
World War 1 began on July 28, 1914. The conflict lasted four years, three months and 14 days, ending on November 11, 1918. The war began because of the assassination of Archduke Franz Ferdinand of Austria. He was heir to throne of Austria-Hungary and his death was the immediate cause of WW1.
Hopefully this could get u started, good luck. I'm sorry, but im not gonna just let someone do your whole project for you. So get out there and start writing! I know your capable of it.
Crops grain and fabrics are the answers