It was, in a number of cultures, a symbol of the sun, with all the positives that go with the sun--light, warmth, and growth.
The swastika of the Nazis wa tilted; in most cultures it looked (to those of us familiar with the English alphabet) like a block letter Z with another block letter Z laid across it, the two lines--vertical and horizontal--intersecting at the middle. The 'arms' (tops and bottoms of the 'Z's') would form a kind of circle if connected by arcs.
It was also used in the Christian faith as a reminder of Christ's crucifixion, and can be found in a number of Catholic churches, including, so they say, the one that Hitler attended as a child.
As a side note, Alexandra, the last czarina of Russia,, collected icons and religious symbols aggressively, including swastikas.
dyed-in-the-wool history nut who once taught the subject