How did hitler's ideas about germans being racially superior lead to the beginning of world war II?

The philosophy of the Nazi Party was based on eugenics, Nordic superiority and the notion that Aryans were a Master race. These ideas were used to justify the extermination of so-called inferior groups. It led to the Holocaust and WWII.

Explanation: Eugenics and racism were at the center of the NAzi project in Europe during WWII.

It caused him to invade Poland, which subsequently caused Britain and other countries to declare war on Germany because of the treaty of WW one.