There are at least four reasons that I can think of on why Europe was on the brink of war in the early 1900�s. The first reason is that Europe�s atmosphere was being destroyed by economic battles and this was because Britain was threatened by Germany�s rapidly growing economy. The second reason was that countries were not as afraid to go war then they used to be because they had militarism in place and the arms race produced supplies to go to war. The third reason is alliances and this happened because powerful nations were insecure about their positions so they made alliances and this ultimately led to the two best known alliances called the Allies and Central Powers. The last reason is just personal pride that each nation had in itself and when opposed no nation would back down.
The same conditions still exist today but in different ways than they did in the early 1900�s. One example is the religion problem throughout the world but mostly in the Middle East which is the main reason those people go to war.