Modern warfare is total, technological warfare
War from the air: German Zeppelin Z3 is brought down in Denmark and put permanently out of action by a storm. Also today, Zeppelin Z4 is taken out of service. Both aircraft have recently been involved in a raid on the coast of Norfolk, England, late in January 1915.
War underground: On Hill 60 on the Ypres salient of the Western Front, the newly formed “mining” unit of the British Royal Engineers explode their first “deep mine” under German trenches, but it is not enough to enable them to take control of the hill.
War under the sea: In Quincy, Massachusets, the US navy lays down the new keels of L-class submarines L-10 and L-11.
War on every terrain: The British War Office experiments today with an early form of tank based on a Holt tractor, but the caterpillar tracks become bogged down in the mud, and the project is abandoned, temporarily at least.