After learning about many of the significant events of the 20th century, I believe the assassination of Archduke Ferdinand was the most significant event. This is because his assassination led to World War 1. At the end of World War 1 The Allies imposed sanctions on Germany that led to the hyper inflation of the German economy. This created poverty and a lot of unemployment in Germany. Many radical political groups were formed during this time. One of the radical groups was the Nazi party which later went on to start World War 2. Therefore the assassination of The Archduke Ferdinand was the single event that caused World War 1 and 2.