Context
In our school district, I strive to limit global announcements to one-per-month and use them exclusively for Canvas-related tips, resources, and learning opportunities. Here's a recent example:
These announcements auto-open and close using the availability dates provided to account admins when creating or editing global announcements in Canvas.
There's just one problem, however. Many teacher users click the 'X' by accident or before reading the announcement's contents when it appears on their Canvas Dashboard. How can they retrieve or regain access to that announcement if it has disappeared?
Suggested Workaround
In Arlington ISD, I've added a publicly-visible course titled 'Global Announcements Archive' as a custom link in our Canvas Help Menu. It looks like this:
When teacher users click on the link, they navigate to a publicly visible Canvas course where we replicate each announcement as a Content Page within a Module. As you'll see, the course's home page is set to Modules.
The Payoff
The primary benefit of creating and maintaining a Global Announcements Archive is that I can direct any user to it in those instances in which they have overlooked, ignored, or accidentally removed an announcement on their Dashboard.
Additionally, it's a useful way for me to revisit past efforts to communicate important information to our Canvas users. I look forward to being able to revisit the archive next school year so as to avoid the need to completely reinvent the wheel in regard to the resources we provide at the beginning of a new term!
If you haven't thought about the potential payoff of creating an Announcements Archive in Canvas, give it some thought. I've definitely found it to be a worthwhile resource to provide to our users! 
