Last 2 paragraphs are basics
Most of Europe's countries were mobilizing their armies. They were gathering large numbers of soldiers, giving them weapons, and stationing them along borders of other countries. Mobilization was seen as an act of war. If you put a huge army with weapons on my front porch, I too would assume you're going to use them on me.
World War actually happened because of a feud with the Austro-Hungarian Empire and Serbia. The Austro-Hungarian heir was murdered, supposedly by the Serbs, and because of this the Austo-Hungarians imposed strict ultimatums on the Serbs. The Serbs had an old alliance with Russia and called them in to help. Because the Serbs called in their alliance with Russia, the Austro-Hungarians called in help from their sister country - Germany.
How it happened shortly from there: Germany saw the mobilization of Russia as an act of war (as previously stated in paragraph one) and declared war on Russia without warning. France got involved because of an alliance with Russia that was already in place. Germany saw France was now involved and went through Belgium to get to France as fast as possible, which then violated Belgium neutrality. Britain had an old alliance with Belgium to protect the small country, and a loose alliance with France (which stated more of an obligation - but they were not forced to defend France), so entered the war to defend Belgium Neutrality. Britain had several colonies around the world which then offered military help, the same goes for France. The US got involved because of unrestricted submarine warfare, after previously warning the Germans to stop unrestricted warfare they began to do so again, so the US joined WWI for the last 7 months.
Basically, mobilization of armies across Europe caused tension. While alliances that were held turned a small Serbia vs. Austria-Hungary war into a world war.
Europe blamed Germany so Germany got mad and they retaliated
The early 1900's were filled with tension in Europe mostly because of formation of international allegiances. Tension was also caused by the infamous Arms Race.
list three causes of tension in Europe in 1914?
Europe was led into warld war1.
Opportunity
in late 1800s and early 1900s the industrial revolution took place
Germany and Great Britain were involved in a naval rivalry in the early 1900s.
Railroad tracks that were built in the early 1900s were constructed from steel. The steel was used to replace rail tracks and railway cars that were built from iron prior to the early 1900s.
Europe was led into warld war1.
the black plague in the early 1900s
asia and europe
The Balkin Peninsula in southeastern Europe was a hot bed of nationalist and the ethnic rivalries in the early 1900s.
noce
freedom
Balkan Peninsula in southeastern Europe
Opportunity
African Americans were moving to the North to work in factories study island sucks
in late 1800s and early 1900s the industrial revolution took place
"Old" immigrants were from Western Europe, and "new" immigrants were from eastern and southern Europe.
Economic opportunity and a measure of political freedom.