On 9 January 1918, some US Army troops clashed with a band of Yaqui native Americans at the Bear Valley in Arizona. The battle was fought on horseback, with cavalry charges and skirmishes on the ground. It was a "minor" clash, but in some ways important because it represents the last phase of the so-called Indian wars between Native Americans and settlers and, in some way, the end of an era that characterized the previous century.
On 15 January of the same year, on the other side of the globe, the HMS Hermes of the British Royal Navy was launched, the first ship in the world built to serve as an aircraft carrier. The ship did not come into operation immediately; he had to wait for the next world war to become a protagonist in the Pacific against the Japanese Empire.
While on one side there was a clash of other times with charges on horseback and clashes with the white weapon, on the other the first technological war of history was fought, with colossal clashes lasting for months, where millions of men fought and died in the anonymity of enormous battles.