Definition of "Happen" :

verb: come to pass

"What is happening?."

verb: come into being; become reality

verb: happen, occur, or be the case in the course of events or by chance

"It happens that today is my birthday."

verb: come upon, as if by accident; meet with

"I happened upon the most wonderful bakery not very far from here."

verb: chance to be or do something, without intention or causation

"I happen to have just what you need!."