swastika
Although it is commonly believed the swastika originates from Hindu and Indian culture, there is also evidence that it was used by ancient Aryan/Indo-Eurpoean tribes as a symbol of the Sun; the Sun being a subject of worship by the ancient tribes. 

It is not unnatural that the swastika was a significant symbol in both Indo-European and Sanskrit cultures sinse the two had a considerable amount of ties.

It also seems logical that Hitler would use a symbol connected to Aryan culture.
There are still uncertainties as to where exactly Hitler acquired his idea of the swastika.  