How do I view notifications?

In Windows there is an action center (notification center) placed on the taskbar in the bottom right corner. It can also be accessed by pressing Windows + A. So I'm just wondering if there's something similar in Ubuntu? I know there are some notifications in the date/time section but I don't find that feature useful.

In the standard Ubuntu Desktop, you view notifications by clicking the date in the top bar. You also can open the notification center with either of the keyboard shortcuts Super+V or Super+M.

I suppose your question is about the standard GNOME Shell desktop, so I don't know if my answer will be relevant to you, because I'm using GNOME Flashback, the "old style" GNOME desktop. There is a "notification area" widget that you can add to the top panel (click Alt+right mouse button on the panel, select "Add to panel" and choose "Notification area" from many available widgets). It behaves a lot like Windows "notification center". When there are any notifications, an envelope icon appears on the panel showing the number of notifications received and when you click on the icon you can view all those notifications and clear them (either individually or all at once) like on the screenshot below: