How did adolf hitler violate the treaty of versailles?

He reoccupied the Rhineland (demilitarized zone), he also rebuilt his army and his air-force but that was around the time when the disarmament conference failed so he used that as his excuse to rearm (other countries were doing the same). 

I think this was in 1939 but he also had a political union with Austria which he wasn't allowed to do. 

The allies did not do anything to prevent him from breaking the terms of the treaty as many people saw that it was too harsh on the germans so there was no point in protecting it.

This was not copied from a website or someone else.