One of the basics of the nazi ideology was that they believed in the superiority of the Aryan German race and that they sought to create a large empire, to ensure that this race had the appropiate "living space"dimenssions, acording to its prestige.
This is why, under the nazi leadership, Germany started to annex territories from neighbour European countries. These expansions and annexations undertaken by nazi Germany, constituted aggressions to other countries and, European systems of alliances remained operative and this triggered the start of WWII.
