What significant military action did Hitler initiate to defy the Versailles Treaty's restrictions?

The significant military action that Hitler initiated to defy the restrictions imposed by the Treaty of Versailles was the rearmament of the German military. The Treaty, concluded at the end of World War I, placed strict limits on Germany’s military capabilities, significantly reducing the size of its army, prohibiting conscription, and banning the production of certain military equipment.

By rearming, Hitler aimed to restore Germany’s military strength and national pride, which he believed had been undermined by the treaty. This move was part of a broader policy of violating the Treaty of Versailles, as it involved not only increasing the size and capacity of the German armed forces but also openly challenging the post-war order established in Europe.

While the establishment of military alliances like the one with Italy, the creation of the Luftwaffe (the German Air Force), and the invasion of neighboring countries were all significant actions that followed, they were part of a strategy that stemmed from the initial act of rearmament, which was a direct challenge to the limitations imposed by the Treaty. Thus, the rearmament of the military serves as a fundamental starting point for understanding Hitler's aggressive expansionist policies during the lead-up to World War II.