21 March

1915 (Sunday)

 * French regain lost trench elements near Notre Dame de Lorette.
 * Severe fighting at Bagatelle (the Argonne).
 * First German airship raid on Paris takes place (see 30 August 1914, and 29 January 1916).
 * Germans re-occupy Memel, East Prussia (see 18 March).
 * Germans abandon attack on Osovyets and withdraw their artillery.
 * Italian military attaché leaves Vienna.