Professor Sachs begins by talking about the age of Britain, or the Pax Britannica, which ended with World War I; and the Treaty of Versailles, which didn’t allow Europe to recover its economic vitality after WWI and which led to World War II. Sachs explains the chronology leading up to World War I, and talks about how this was the first truly industrial war with a high death toll. The end of World War I saw the collapse of four empires: the Prussians, the Romanovs, the Habsburgs, and the Ottomans, and the Treaty of Versailles prevented an economic recovery in Europe, which led to a significant economic recession. In Germany, Adolf Hitler became chancellor and was able to capitalize upon German unrest to motivate the country to start World War II and to create his own fascist empire. The United States came out of World War II the most powerful economy in the world.