Happen (verb)

1. To occur, take place.
2. To come to pass.
3. To transpire.

Origin:

From middle english happenen, from old english happian.

Examples:

1. What happened to the missing cat?
2. Many interesting things happen on this street.
3. It is always a mystery what will happen next.
4. A lot has happened since I last saw you.
5. The accident happened so quickly that nobody saw it.