How did WWI lead to World War 2?

How much percent of the Red River Rebellion were Europeans? Why were racial tensions high during World War 1? What is the world's oldest currency still in use? What was The greatest public health disaster during the mid-19th century? What lines was Anglo Saxon society structured along? What are the titles given to Charlemagne by pope? Who is group rose to power after ww1? What European nations controlled Africa in the early 1900? Who was Nebuchadnazzar? What is the greatest gift to the world? After World War 2 what European countries became communist? After gaining independence what was a major factor that prevented many African countries from having strong economies? What best explains why trade among the colonies flourished? How does balboa rationalize his behavior to answer the monks criticism of him? Who is well known for Pan Africanist missionary work that included providing economic role model for Africans? What plaza was the site of decapitations in French Revolution? What continent from which many slaves were brought to the new world? What area did Zebulon Pike explore after he discovered Pike's Peak? Was Hudson an a explorer of the new world? How did progressive idea influence the roles of women during ww 1?

How did WWI lead to World War 2?