A. uneven heating of the air
In 1871 two new major states of Europe had been formed—the German Empire and the kingdom of Italy. The new German Empire, under the hand of Otto von Bismarck<span>, was steered carefully, always with an eye upon France, for the Franco-Prussian War (1870–71) had left France thirsting for revenge and for recovery of the lost provinces of Alsace and Lorraine.</span>
Around that time most of the Spanish settlements were <span><em>centered around forts</em>.</span>