The swastika is a cross with its arms bent at right angles to either the right or left. In geometric terms, it is known as an irregular icosagon or 20-sided polygon.

The word is derived from the Sanskrit "svastika" and means "good to be". In Indo-European culture it was a mark made on people or objects to give them good luck.

It has been around for thousands of years, particularly as a Hindu symbol in the holy texts, to mean luck, Brahma or samsara (rebirth). It can be clockwise or anti-clockwise and the way it points in all four directions suggests stability. Sometimes it features a dot between each arm.

The rise of Nazism made this symbol inappropriate, especially in the western world.
Please, note that the symbol on the temple roof has absolutely nothing to do with the Nazism.