How to view a calendar event after notification

How do I view the events in my Calendar app that it's alerting me to? The calendar app shows a red number on its icon for an event(s) that is supposed to be occurring soon (or has already occurred). If I open the Calendar, there is no way to know what event that number is referring to.

I would expect those notifications to be up in the notification bar at the top of the phone's screen.
Which calendar app are you using?