Chinese paper was a huge accomplishment with a light but durable resource to write on that is also cheap.
Bonus fact: the first piece of paper had Hemp in it
The German U-boats blocked British Isle and attacked merchant ships affecting the trading business of US with British, but at some stage the U-boats started to attack ships taking the lives of unarmed passengers, as with the Lusitania ship, which 120 American died. The Germans were asked to stop the attacks but they did not and many US ships sank, shedding off US citizens lives. The submarine warfare enraged the US neutrality which then turned against the German and declared war on March 1 in 1917.
Feudalism is the denomination of the predominant political system in Western Europe of the middle centuries of the Middle Ages (between the 9th and 15th centuries), and in Eastern Europe during the Modern Age, characterized by the decentralization of political power; based on the diffusion of power from the top (where in theory were the emperor or kings) to the base where local power was exercised effectively with great autonomy and independence by an aristocracy, called nobility.