A wall message warned of impending reboot or shutdown, but I missed the details. How can I obtain them?

While some output was being written to my terminal, a wall message passed by. It went too fast for me to read it. All I could tell was Broadcast message from The system is going down for And even most of that is an educated guess. Crucially, I missed *when* it's going down. 20 minutes? 2 hours? 24 hours? Can I either reread the wall message, or look for planned shutdowns/reboots somewhere? I'm just an ordinary user without root.