The Facebook calendar is checked (picture below), and while the events do appear on my laptop, they won't appear on my iPhone calendar. I uninstalled Facebook and Messenger, then logged out of my gmail account to remove all calendars. It was odd that when I did this, the Facebook calendar option stayed yet the rest left (second picture), but after reinstalling everything the events still won't show up.
Best Answer
On your desktop, Look in the right-hand pane on the Event page in Facebook. Find this section...
The last two links are webcal links which will let you subscribe via iCalendar on your Mac. Then, it will sync to your device if you have iCloud calendar sharing on. Roundabout, yes.