It's not the only anomaly. There was a previous period of long peace between 1815 and 1914, between the Napoleonic Wars and WW1.
This balance of power was carefully set up in the Congress of Vienna following the (first) defeat of Napoleon, and was ended by the ambitions of a Kaiser who desired the prestige of globe-spanning empire yet couldn't diplomacy his way out of a wet paper bag to realize that empire without bumbling into war.
This balance of power was carefully set up in the Congress of Vienna following the (first) defeat of Napoleon, and was ended by the ambitions of a Kaiser who desired the prestige of globe-spanning empire yet couldn't diplomacy his way out of a wet paper bag to realize that empire without bumbling into war.